tag:blogger.com,1999:blog-56772355947203307032024-03-21T21:59:47.390-07:00CRF_NubiaNubia A. Navarro C.http://www.blogger.com/profile/16124874914747829398noreply@blogger.comBlogger43125tag:blogger.com,1999:blog-5677235594720330703.post-46075759123184782432010-07-25T19:49:00.000-07:002010-07-25T19:49:06.771-07:00Dielectric Resonator Oscillators<div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Dielectric Resonator Oscillators (DRO) are used widely in today's electronic warfare, missile, radar and communication systems. They find use both in military and commercial applications. The DROs are characterized by low phase noise, compact size, frequency stability with temperature, ease of integration with other hybrid MIC circuitries, simple construction and the ability to withstand harsh environments.</div><div style="text-align: justify;"></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">These characteristics make DROs a natural choice both for fundamental oscillators and as the sources for oscillators that are phase-locked to reference frequencies, such as crystal oscillators.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">This paper summarizes design techniques for DROs and the voltage- tuning DRO (VT-DRO), and presents measured data for them including phase noise, frequency stability and pulsing characteristics.</div><div style="text-align: justify;"><br />
</div><div style="text-align: center;"><strong><span style="font-size: large;">Design Techniques</span></strong></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">The design technique we will discuss is for a dielectric resonator (DR) to be used as a series feedback element. Practically, a GaAs FET or a Si-bipolar transistor is chosen as the active device for the oscillator portion of the DRO circuit. The Si-bipolar transistor is generally selected for lower phase noise characteristics, while the GaAs FET is required for higher frequencies.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">For example, a DRO with a DR as a series feedback element can be designed using following design procedure: </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">1. Select an active device that is capable of oscillation at the design frequency, and use the small signal S-parameter of the device for the design. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">2. Add a feedback circuit to ensure that the stability factor of the active device with the feedback circuit is less than unity with enough margin. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">3. Create an active one-port analysis that consists of the active device, the feedback circuit, the matching network and the load as shown as figure1. Optimize Za (?) with the parameters in the feedback circuit and in the matching network to ensure that Ra (?0) is less than or equal to -25 ohms and Xa (?) has the possible maximum variation near resonance in order to insure high circuit Q. </div><br />
<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhI759xc4KCL1_zhNvAFip9hImBdHMNUJyaV2YaWEk48r8Twj88aTBVZE8DCc8PGlPe8jZ-azghj6D-2D9kbFPZ7KcQrewzEmim6laJdUu0u4894Bu7jz6cqr_Wh3V_I6dwuIj07R6zKpje/s1600/8.bmp" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" hw="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhI759xc4KCL1_zhNvAFip9hImBdHMNUJyaV2YaWEk48r8Twj88aTBVZE8DCc8PGlPe8jZ-azghj6D-2D9kbFPZ7KcQrewzEmim6laJdUu0u4894Bu7jz6cqr_Wh3V_I6dwuIj07R6zKpje/s320/8.bmp" /></a></div><div class="separator" style="clear: both; text-align: center;"><strong><em>Figure 1. Schematic diagram of the series feedback DRO</em></strong> </div><br />
<div style="text-align: justify;">Determine the electrical spacing of the dielectric resonator such that the reactance it presents to the base or gate of the transistor is the negative of Za. The characteristic impedance of the output transmission line, Zg, is usually selected to be 50 ohms. </div><div style="text-align: justify;"></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">The open stub (characteristic impedance of 50 ohms), which is terminated at the source end of the FET, serves as the feedback element. By adjusting the electric length of the feedback stub, various port impedance characteristics for Za (?) in the band of interest (6-15 GHz) can be obtained.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">From the port reactance characteristic, we observe that the shorter the electric length of feedback stub, the more rapid the port reactance change with frequency. On the other hand, for the active port, a shorter feedback stub induces higher negative resistance. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Finally, negative resistance is reduced if the electrical length of the feedback stub is less than 25 degrees. Taking etch tolerances into consideration, the length of the feedback stub is chosen as 45 degrees. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;"><strong><em>10 GHz Example:</em></strong></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">The resultant input impedance of the active port is Za = -40.8 -j62.5 ohms at the desired frequency. The negative resistance of -40.8 ohms is sufficient to allow the transistor to build up and sustain oscillation at the desired frequency. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">It remains to determine the length of a 50 ohm terminated microstrip line between the coupling plane of the DR and the gate terminal of the active device. We know that the load must have a reactance XI = 62.5 ohms to resonate with the reactance of the active device input (gate) port.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Looking toward the DR from this port, the circuit appears as if it were an open circuited transmission line stub for which the open circuit appears at the equivalent coupling plane of the DR, about equal to the location of the DR's centerline drawn perpendicular to the line to which it couples. Accordingly, its reactance is XI = Zg cot (?g), from which the spacing of the DR can be determined. In the present series feedback example, the computed electric length is 141.3 degrees at 10.4 GHz. A photograph of the 10.4 GHz DRO is shown in </div><div style="text-align: justify;"><br />
</div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhcllbYut6lm0uCNjivJm6eKepopju5LW3J7jgbH_2t635OBUkZZcD2zZ7VxrJBvyNK6ylo3-zEgLnV5PfZxZFjArIBMP5TzS6RNBkbv8xGXcsCVnl3eyZKSwlHnhxsnNQzJhY-qj0V4qUN/s1600/9.bmp" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" hw="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhcllbYut6lm0uCNjivJm6eKepopju5LW3J7jgbH_2t635OBUkZZcD2zZ7VxrJBvyNK6ylo3-zEgLnV5PfZxZFjArIBMP5TzS6RNBkbv8xGXcsCVnl3eyZKSwlHnhxsnNQzJhY-qj0V4qUN/s320/9.bmp" /></a></div><div class="separator" style="clear: both; text-align: center;"><em><strong>Figure 2. Photograph of a 10GHz DRO.</strong></em></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Small signal S parameters are used in the design, whereas in reality the oscillator's voltage amplitudes increase until saturation, at which the DRO reaches its steady state output power. This saturation, by definition, corresponds to the high level S parameter case. Nevertheless, designs based upon the small signal behavior are found to yield a good first order solution, requiring minor adjustment for high level operation at the desired frequency.</div><br />
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The frequency stability of the DRO over temperature is selected by taking into account the total circuit. In other words, the temperature characteristics of the supporting structure, the epoxy with which the DR is attached, the RF device, and the circuit housing must be accounted for during selection of the dielectric resonator material and temperature coefficient. <br />
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A frequency stability of 3 parts per million per degree Centigrade (3 ppm/C°) for a DRO operating around 10 GHz is typically achievable. This corresponds to a frequency shift of 30 kHz per Centigrade degree shift. <br />
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<div style="text-align: center;"><strong><span style="font-size: large;">Differences in DR Material</span></strong></div><br />
Besides temperature coefficient, the DR is selected for its size and dielectric constant. Figure 3 shows that the size of the DR (the thickness to diameter ratio of a DR is generally kept to 0.4 for the widest mode separation) is inversely proportional to the frequency of the DRO for the same dielectric material. <br />
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<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgaWceTl5LfLSyxyxIin4h7Mm1taX9naKz5LKFLhRvMskcCAkUzSB-cBkA-xW06VKtoslzTZpeC9u8v4kafU-8xdlcW9F_e9cwAl1b4g9K8v8fY3c6g-gTqMPuHS419k-S4lJFvTgUeuHJA/s1600/10.bmp" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" hw="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgaWceTl5LfLSyxyxIin4h7Mm1taX9naKz5LKFLhRvMskcCAkUzSB-cBkA-xW06VKtoslzTZpeC9u8v4kafU-8xdlcW9F_e9cwAl1b4g9K8v8fY3c6g-gTqMPuHS419k-S4lJFvTgUeuHJA/s320/10.bmp" /></a></div><div class="separator" style="clear: both; text-align: center;"><strong><em>Figure 3. Picture of DRO of different diameters for close to the same freq.</em></strong></div><br />
<div style="text-align: justify;">On the other hand, Figure 4 shows that dielectric resonators of almost the same size but with different dielectric materials can be used for DROs of various frequencies. The 12 GHz DRO with integral amplifier shown has the smallest size (0.515" x 0.535" x 0.375") ever reported using hybrid MIC techniques, yet it delivers more than 20 dBm of output power at 105 C°. </div><br />
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<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiJIA47CNzd689h0uu5-kmSgMw7bW_rTn6eTsJPHf_Vrml1rsDxqpg7ARfqaaTsDGD7YQGbDi0JBHyX7W7FeQOobtT_C3YYkWaLsoH9jwiDFvKKkXbNIyOPLYhOBcIhKvUjuHV9ubeMH6Rw/s1600/11.bmp" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" hw="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiJIA47CNzd689h0uu5-kmSgMw7bW_rTn6eTsJPHf_Vrml1rsDxqpg7ARfqaaTsDGD7YQGbDi0JBHyX7W7FeQOobtT_C3YYkWaLsoH9jwiDFvKKkXbNIyOPLYhOBcIhKvUjuHV9ubeMH6Rw/s320/11.bmp" /></a></div><div class="separator" style="clear: both; text-align: center;"><em><strong>Figure 4. DROs of different frequencies with different dielectric material used for the CRs</strong></em> </div><br />
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<div style="text-align: center;"><strong><span style="font-size: large;">Electronic Frequency Tuning</span></strong></div><br />
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<div style="text-align: justify;">Frequency tuning of a DRO can be achieved by using voltage controlled diodes (varactors). The circuit configuration for coupling the varactors to the DR consists of an additional line paralleling that which couples the DR to the active device, and placed on the opposite side of the DR see figure 5. In the example shown two varactors are attached to the ends of a microstrip half wavelength resonator having characteristic impedance Zt. </div><br />
<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj4Qqf1RPDMKxEVMSPsPBdn6F2mfG5_iVdW47WeWWfZS6Q8pdIh33ntavsnHn84Fbvy2g-JwRLBbTy6hla2a3ZWdhnGzUCGU5PRSWyjXbg4-JwANB4-aJe3qkwYIUTcvCwWmwTe2V7biLL0/s1600/12.bmp" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" hw="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj4Qqf1RPDMKxEVMSPsPBdn6F2mfG5_iVdW47WeWWfZS6Q8pdIh33ntavsnHn84Fbvy2g-JwRLBbTy6hla2a3ZWdhnGzUCGU5PRSWyjXbg4-JwANB4-aJe3qkwYIUTcvCwWmwTe2V7biLL0/s320/12.bmp" /></a></div><div class="separator" style="clear: both; text-align: center;"><em><strong>Figure 5a. Schematic of VT-DRO. </strong></em></div><div class="separator" style="clear: both; text-align: center;"><br />
</div><div class="separator" style="clear: both; text-align: justify;">At the DR plane of coupling, the transmission line can be treated as two quarter-wavelength impedance transformers (or, more precisely two impedance inverters) terminated with two tuning varactors. The varactors' capacitive variation at the end of the inverter is transformed into inductive variation at the plane of the coupling by the impedance inverter. </div><div style="text-align: justify;"></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">By increasing the coupling between the DR and the varactor/microstrip line, the tuning bandwidth of the DRO can also be increased. There is a trade-off for wider tuning bandwidth in that degraded phase noise and poorer frequency stability results, mainly due to the resultant equivalent degradation in the unloaded Q of the dielectric resonator.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Keeping this in mind, it is necessary that the electrical tuning band of the DRO be wider than the anticipated frequency drift of the oscillator versus temperature.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">In summary, coupling the dielectric resonator to the tuning line and coupling the tuning circuit to the oscillator circuit must be kept in balance. Than can easily be done without significantly degrading the phase noise characteristics or temperature performance. </div><div style="text-align: justify;"><br />
</div><div style="text-align: center;"><span style="font-size: large;"><strong>Temperature Compensation DROs</strong></span></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Electrical tuning of a DRO can be used to compensate for frequency drift over temperature. The DRO frequency change over temperature is measured for various temperatures to establish a frequency drift profile. A correction profile is calculated and a correction circuit consisting of thermistors (resistors that very with temperature) and resistors is calculated. This temperature sensor information is converted into proper tuning voltage and is fed into the tuning port of the DRO.</div><div style="text-align: justify;"><br />
</div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhANRhNfdtMjkaVuKUU5C6z4lxBBoGbFkFnBcyCfqSqCsQgZ6rpWLu2AI303H32RfGJD6q0Nf7CAFnyrVvbWeH9fuJ6IYr9oRTcirFzxakXFRD_p7AKWVHglRhuCNo-cOUqrcl68sPnslZs/s1600/13.bmp" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" hw="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhANRhNfdtMjkaVuKUU5C6z4lxBBoGbFkFnBcyCfqSqCsQgZ6rpWLu2AI303H32RfGJD6q0Nf7CAFnyrVvbWeH9fuJ6IYr9oRTcirFzxakXFRD_p7AKWVHglRhuCNo-cOUqrcl68sPnslZs/s320/13.bmp" /></a></div><div style="text-align: center;"><em><strong>Figure 5b. Block diagram of Temperature Compensated DRO (TC-DRO). </strong></em></div><br />
<div style="text-align: justify;">This compensation technique is well known in TCXOs and the three or four typical compensation profiles are well established and easily fabricated.</div><div style="text-align: justify;"></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">The temperature compensated DROs using the analog approach exhibit + /- 0.3 ppm per degree C stability with DRO output frequencies up to 20 GHz from and over the temperature range -54 C to + 105 degrees C.</div><br />
<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhznDiTy7F46P8ShXpPLFKVq4vKvbwaNIW6gtXvC8hOjrfJPih8iX0MPgoN26uYwHkqB04-nEmG5gDEn8LCICr02rQDyHmWKZcwp4V2CkXya5nKkhWliSR976e41zI4pmcly-cWswy_vGZh/s1600/14.bmp" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" hw="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhznDiTy7F46P8ShXpPLFKVq4vKvbwaNIW6gtXvC8hOjrfJPih8iX0MPgoN26uYwHkqB04-nEmG5gDEn8LCICr02rQDyHmWKZcwp4V2CkXya5nKkhWliSR976e41zI4pmcly-cWswy_vGZh/s320/14.bmp" /></a></div><div class="separator" style="clear: both; text-align: center;"><em><strong>Figure 6. TC-DRO temperature profile.</strong></em> </div><div class="separator" style="clear: both; text-align: center;"><br />
</div><div class="separator" style="clear: both; text-align: justify;">The analog approach is smooth and continuous with no thermal toggling. The digital approach of temperature compensation also can provide similar frequency stability but much more complex circuitry is required. </div><div style="text-align: justify;"></div><div style="text-align: justify;"><br />
</div><div style="text-align: center;"><strong><em><span style="font-size: large;">Phase Locked Loop DROs</span></em></strong></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">The VT-DRO can be used in conjunction with a sampling phase detector (SPD) to form the correction loop of a phase-locked source. The main advantage of PLL-DRO is its superior phase noise performance. Inside the loop, the phase noise has the characteristics of a frequency up-converted crystal oscillator [20log(N)] and outside the loop, the phase noise is the VT-DRO. The loop bandwidth can be shifted in frequency to minimize the loop circuit noise peaking.</div><div style="text-align: justify;"><br />
</div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiwop0N46Vvt75ldQ1qNzo3S-F7rY9Sk8lTAUOX41Z2oHyXjUovA9psffzZCBOoniXxF_4-jbpp6oO3aeabawHP5wRtzB1nUfuBO_XqcBxZEsMTo8XaKV6HLfAZnRhARHf9fKCngBensiyW/s1600/15.bmp" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" hw="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiwop0N46Vvt75ldQ1qNzo3S-F7rY9Sk8lTAUOX41Z2oHyXjUovA9psffzZCBOoniXxF_4-jbpp6oO3aeabawHP5wRtzB1nUfuBO_XqcBxZEsMTo8XaKV6HLfAZnRhARHf9fKCngBensiyW/s320/15.bmp" /></a></div><div class="separator" style="clear: both; text-align: center;"><strong><em>Figure 7. Noise plot of PLL-DRO </em></strong></div><div class="separator" style="clear: both; text-align: center;"><br />
</div><div class="separator" style="clear: both; text-align: justify;">The tuning sensitivity ratio (frequency change versus control voltage) is relatively consistently, which makes the loop circuit relatively consistent. The low phase noise and small circuit size make the VT DRO very attractive in phase-locked source applications. </div><div style="text-align: justify;"></div><div style="text-align: justify;"><br />
</div><div style="text-align: center;"><span style="font-size: large;"><strong>Phase Noise</strong></span></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">One of the important characteristics of a DRO is its phase noise at 10 kHz or higher away from the carrier. The phase noise of a DRO is dependent upon the active device used, the coupling of oscillation power to the DR, and the amount of power delivered to load. Figure 10 shows the typical phase noise characteristics of a DRO using Si-bipolar transistors and GaAs FETs. The Si-bipolar transistor provides about a 10 dB improvement in phase noise, which is generally believed to be contributed by Vfm noise of the GaAs FETs. Phase noise increases with the square of operating frequency, thus to obtain the phase noise level of a DRO at frequencies other than 10 GHz, add 20x log10 [f(GHz)/10] to the values shown in Figure 10. For example, corresponding phase noise will be 6 dB greater for a 20 GHz DRO.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">As more energy is stored in the dielectric resonator, the temperature characteristic of the DRO more closely follows that of the DR, however more of the active device's power is dissipated in the DR, leaving less for output. Also the phase noise of the DRO also may degrade. Therefore, some compromise often must be made between the DRO's temperature stability and phase noise. </div><div style="text-align: justify;"><br />
</div><div style="text-align: center;"><strong><span style="font-size: large;">Pulsing Characteristics</span></strong></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">For some applications it is desirable that the output power of the DRO be turned on and off, subjected to pulsing from TTL control signals. Pulsing circuitries can be placed at the drain (Figure 12a) or at the ground (Figure 12b). Both circuits yield similar pulsing rise time, defined as the time between 50% TTL input and 90% RF output. A rise time 600 nsec has been obtained for a 16 GHz DRO with 20 dBm output power and phase noise of 86 dBc/Hz at 10 kHz from the carrier. The high unloaded Q (Qu) nature of the DR requires longer time to build up the energy in the resonator compared a free running oscillator.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">To increase the pulsing speed, relatively high loss dielectric resonator material can be used together with tighter coupling of the microstrip line to the DR, at the expense of reduced unloaded Q and significant impact on phase noise and frequency stability. While the frequency stability of a DRO can be compensated by using a DR of proper temperature characteristics, the phase noise appears to be the parameter that must be traded off for faster rise time pulsing. A similar design of a DRO at 16 GHz, when optimized for pulse rise time, exhibits less than 100 nsec rise time but a phase noise degraded to 73 dBc/Hz at 10 kHz from the carrier.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">The settling time of the fast pulsing DRO is less than 100 nsec when the frequency is measured with 80 +1/ -100 kHz referenced to the frequency measured at 500 nsec and drift within +1/ -100 kHz from 500 nsec to 1 sec. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;"><strong>Fuente:</strong> <a href="http://www.gedlm.com/DRO/DRO.asp">http://www.gedlm.com/DRO/DRO.asp</a></div><div style="text-align: justify;"><strong>Ver blogger original</strong>: <a href="http://nubia-anc.blogspot.com/">http://nubia-anc.blogspot.com/</a></div><div style="text-align: justify;"><strong>Materia: CRF</strong></div>Nubia A. Navarro C.http://www.blogger.com/profile/16124874914747829398noreply@blogger.com0tag:blogger.com,1999:blog-5677235594720330703.post-71029041271170237342010-07-25T19:28:00.000-07:002010-07-25T19:28:13.669-07:00An Invisibility Cloak may be a Reality Soon<div style="text-align: justify;">A Michigan Technological University scientist has worked on making an invisibility cloak, and who knows one day you might just be the owner of one!</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Elena Semouchkina, an associate professor of electrical and computer engineering at Michigan Tech, has found ways to use magnetic resonance to capture rays of visible light and route them around objects, rendering those objects invisible to the human eye.</div><div style="text-align: justify;"><br />
</div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh3OZjZL2oqA0-krHZVnwRNPepaF0H5Fxi5zwf8NHjNvqR8EaAzWjWQS7POTa5bMfryC7DPdNtApx7U0FslKecE54iinLp3kKulpJ2NJFQPwj09Ye_yBsxTHiv99k0k3hunAu4xFeMJKtKR/s1600/7.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" hw="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh3OZjZL2oqA0-krHZVnwRNPepaF0H5Fxi5zwf8NHjNvqR8EaAzWjWQS7POTa5bMfryC7DPdNtApx7U0FslKecE54iinLp3kKulpJ2NJFQPwj09Ye_yBsxTHiv99k0k3hunAu4xFeMJKtKR/s320/7.jpg" /></a></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">In a paper appearing in the journal Applied Physics Letters, Semouchkina and colleagues <strong>describe developing a nonmetallic cloak that uses identical glass resonators made of chalcogenide glass, a type of dielectric material (one that does not conduct electricity).</strong> In computer simulations, the cloak made objects hit by infrared waves - approximately one micron or one-millionth of a meter long - disappear from view. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Earlier attempts by other researchers used metal rings and wires. Semouchkina said: "Ours is the first to do the cloaking of cylindrical objects with glass." </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Her invisibility cloak uses metamaterials, which are artificial materials having properties that do not exist in nature, made of tiny glass resonators arranged in a concentric pattern in the shape of a cylinder. The "spokes" of the concentric configuration produce the magnetic resonance required to bend light waves around an object, making it invisible. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Semouchkina and her team now are testing an invisibility cloak rescaled to work at mocrowave frequencies and made of ceramic resonators. They're using Michigan Tech's anechoic chamber, a cave-like compartment in an Electrical Energy Resources Center lab, lined with highly absorbent charcoal-gray foam cones.</div><br />
<strong>Fuente</strong>: <a href="http://www.medindia.net/news/An-Invisibility-Cloak-may-be-a-Reality-Soon-71765-1.htm">http://www.medindia.net/news/An-Invisibility-Cloak-may-be-a-Reality-Soon-71765-1.htm</a><br />
<strong>Ver blogger original</strong>: <a href="http://nubia-anc.blogspot.com/">http://nubia-anc.blogspot.com/</a><br />
<strong>Materia: CRF</strong>Nubia A. Navarro C.http://www.blogger.com/profile/16124874914747829398noreply@blogger.com0tag:blogger.com,1999:blog-5677235594720330703.post-49653584562049768772010-07-25T19:18:00.000-07:002010-07-25T19:18:57.404-07:00Hittite Microwave Corporation to Release Second Quarter<div style="text-align: justify;"><br />
</div><div style="text-align: justify;"><strong><em>CHELMSFORD, Mass., Jul 01, 2010 (BUSINESS WIRE) -- Hittite Microwave Corporation /quotes/comstock/15*!hitt/quotes/nls/hitt (HITT 47.79, +0.83, +1.77%) plans to announce its financial results for the second quarter ended June 30, 2010 after the close of market on Thursday, July 22, 2010.</em></strong> </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">In conjunction with the release, Hittite Microwave will conduct a conference call at 5:00 p.m. ET on July 22, 2010, hosted by Mr. Stephen G. Daly, Chairman, President and Chief Executive Officer, and Mr. William W. Boecke, Vice President and Chief Financial Officer. A live webcast of the call will be available online on the Hittite Microwave website. To access the live webcast, go to the Investor page of the Hittite Microwave website at www.hittite.com and click on the webcast icon located under the News & Events section. Hittite Microwave encourages each visitor to review the site prior to the call to ensure that the visitor's computer is configured properly. A telephonic replay of the call also will be available for one week after the live call by dialing (303) 590-3030 access code 4325633. The webcast replay of the call will also be available after the live call by visiting the Investor page at www.hittite.com. </div><div style="text-align: justify;"></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;"><em><strong>About Hittite Microwave Corporation</strong></em> </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Hittite Microwave is an innovative designer and developer of high-performance integrated circuits, or ICs, modules, subsystems and instrumentation for technically demanding radio frequency, or RF, microwave and millimeterwave applications. Products include amplifiers, attenuators, broadband time delay, comparators, data converters, DC power conditioning, DC power management, dielectric resonator oscillators, filters-tunable, frequency dividers and detectors, frequency multipliers, high speed digital logic, interface, limiting amplifiers, mixers and converters, modulators and demodulators, mux/demux, oscillators, passives, phase lock loop (PLL), PLL with integrated VCOs, phase shifters, power detectors, sensors, switches, synthesizers, transimpedance amplifiers and variable gain amplifiers. Hittite's products are used in a variety of applications and end markets including automotive, broadband, cellular infrastructure, fiber optic, microwave and millimeterwave communications, military, space, and test and measurement. The company utilizes radio frequency integrated circuits (RFIC), monolithic microwave integrated circuits (MMIC), multi-chip modules (MCM) and microwave integrated circuit (MIC) technologies. The company is headquartered in Chelmsford, MA. </div><div style="text-align: justify;"><br />
</div><strong>Fuente:</strong> <a href="http://www.marketwatch.com/story/hittite-microwave-corporation-to-release-second-quarter-2010-financial-results-on-july-22-2010-2010-07-01?reflink=MW_news_stmp">http://www.marketwatch.com/story/hittite-microwave-corporation-to-release-second-quarter-2010-financial-results-on-july-22-2010-2010-07-01?reflink=MW_news_stmp</a> <br />
<strong>Ver blogger original</strong>: <a href="http://nubia-anc.blogspot.com/">http://nubia-anc.blogspot.com/</a> <br />
<strong>Materia: CRF</strong>Nubia A. Navarro C.http://www.blogger.com/profile/16124874914747829398noreply@blogger.com0tag:blogger.com,1999:blog-5677235594720330703.post-37917240596824446932010-07-25T19:11:00.000-07:002010-07-25T19:13:03.028-07:00EM simulation for EMC: keeping a lid on interference<div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Simulating your product’s EM (electromagnetic) radiation will help ensure that you pass FCC (Federal Communications Commission) and CE (Conformité Européenne) tests and will keep your project on schedule. Every product must have EMC (electromagnetic-compatibility) tests. The FCC requires that you test your products to ensure that EM radiation will not cause interference with radios, phones, and TVs. In addition to testing for EM radiation, your product must also exhibit electromagnetic immunity, meaning that a strike from a defined EM pulse will not significantly disturb the product’s performance (Reference 1).</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;"></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg_mrNowamZekFLDvSGK6F92PPnFIF9MOdFbLv1j28XAGpIH06CxPzOHczhViXEyePNKXDRkqW0a3zA2Z1HuwY1Ths-ksihBYgTwfXRAdlT9oCbrHlSrwRvwPktvIA5WVdtmBjVcF-NBPOZ/s1600/5.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" hw="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg_mrNowamZekFLDvSGK6F92PPnFIF9MOdFbLv1j28XAGpIH06CxPzOHczhViXEyePNKXDRkqW0a3zA2Z1HuwY1Ths-ksihBYgTwfXRAdlT9oCbrHlSrwRvwPktvIA5WVdtmBjVcF-NBPOZ/s320/5.jpg" /></a></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">You need sophisticated software tools to perform EM simulations. These simulations must take into account both small and large features over a broad frequency range (Figure 1). You must also select an appropriate simulation method, which can be either a timedomain technique, such as FEM (finite-element method), or a frequency-based one, such as MOM (method of moments). For the largest problems, you need to break the simulations into subdomains or use asymptotic-solutions techniques.</div><div style="text-align: justify;"><br />
</div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg7vzTl33U0OelMy0-1T2n8sSmqUWSV8eg27uMx2kA-XoSni7rJvpggkHvDZ8AHeftftBRDCpgXfrESHWwppB4qEuXGXxyesnWA6LhX4bp9tnHhq0X1Bdvx-p5HaO0TTaPhrgCwcbhwx7Cg/s1600/6.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" hw="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg7vzTl33U0OelMy0-1T2n8sSmqUWSV8eg27uMx2kA-XoSni7rJvpggkHvDZ8AHeftftBRDCpgXfrESHWwppB4qEuXGXxyesnWA6LhX4bp9tnHhq0X1Bdvx-p5HaO0TTaPhrgCwcbhwx7Cg/s320/6.jpg" /></a></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Once you have a powerful computer and the right software, you must place physical and electrical data into the software using database importation or by feeding in mechanical configurations with Gerber and DXF (Drawing Exchange Format) files and manually entering dielectric constants and board-stackup specifications. Finally, you must provide a stimulus to the software, either with Spice or S-parameter data or with a near-field-simulation result from a previous simulation on a subsystem in the product.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;"><strong><em>Spice versus field solver</em></strong> </div><div style="text-align: justify;"></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">You cannot use Spice to simulate EMC because Spice is a matrix-math computational solver for Kirchhoff’s equations that uses lumped-element models of discrete components. At best, you can use Spice to model a lossy transmission line to define what happens to the signal, but it does not reveal which fields radiate into space. For this problem, you need a field-solver simulation (Reference 2). A field solver uses finite elements, meshing, and iteration to solve Maxwell’s equations for your circuit design. EM-simulation software must account for the mechanical configuration and the materials you use in the design (see sidebar “Computer power”).</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">The highest frequencies you are trying to simulate and the size of the circuit dictate the scope of the field-solver problems you will encounter. Wavelengths are 30m at 10 MHz, meaning that a 1-cm trace is much smaller than the wavelength. The software would not have to mesh the trace into smaller sections to iterate toward a solution. The 30m wave acts almost uniformly on the 1-cm trace.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Imagine a 10-GHz radar signal with a 2-cm wavelength bouncing off a battleship. The field-solver software must break the battleship into billions of tiny meshes, fitting 10 or even 100 into each square centimeter of the ship’s surface. The surface of a metal battleship is not purely reflective, so the software must do 3-D meshing and has even more elements to compute because it must also do the interior areas. The workstation that runs the software needs hundreds of gigabytes of memory to store intermediate calculations for the meshes, and it would take months to solve for the fields over this large area. You can solve the memory problem by breaking the problem into domains and solving them iteratively, but that approach would take even longer.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">When you test for EMC, small mechanical features result in big changes in performance. A slot in a cover, a misrouted trace, or an aluminum heat sink on an IC package can all cause your product to fail EMC-radiation testing. These mechanical features serve as antennas, so they also receive energy from their surroundings, giving your product poor electromagnetic immunity. The standards require compliance to frequencies of 960 MHz and beyond. For this reason, simulating for EMC is a broadband problem with heavy computational requirements. You must simulate for those frequencies; thus, simulating a large system takes an unacceptably long time. The complexity of the problem is monstrous even for a rather simple product. Also, multiple phenomena, including electrical fields radiating from traces, magnetic fields from inductors, and both types of fields radiating into and from cables, are responsible for EMI (electromagnetic interference).</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">A typical EM-simulation strategy divides the problem into pieces and depends on both relative and absolute measurements. You need to know how customers will use the product, divide your EMC analysis into manageable pieces, and then evaluate those pieces as they relate to the whole problem. The principle of superposition can be a big help. It states that, for all linear systems, the net response at a given place and time that two or more stimuli cause is the sum of the responses that each stimulus individually would have caused. If three main contributors are affecting your EMI signature, you can individually simulate each one, with different techniques if necessary, and then add the results in an rms (rootmean-square) fashion if they are not related. Sometimes, though, one system affects the other, and they do interact.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Once you have simulated the PCB (printed-circuit board), you represent that simulation as a radiating model that you then plug into a larger assembly. Even if you can use likely signals to simulate the radiation from your PCB, you may also have a few switching power supplies that have not only electric fields, but also magnetic ones. A case surrounds these components, and the cables from the product are antennas that radiate energy to make you fail EMC testing and receive energy to make your circuit fail immunity tests. You may also have to decide how disparate radiation patterns add up to a total emissions level. That decision may bring up the ugly reality of nonlinear circuits, such as RF-power amplifiers that you drive into saturation to get good efficiency. Superposition techniques don’t work in nonlinear systems and may cause you to underestimate the radiation from the circuitry.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;"><strong><em>Selecting a technique</em></strong></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">The mathematicians and software wizards who work at field-solver companies have developed many methods to help you do EM simulations. You can use 2-D simulation programs, such as HyperLynx and SIwave (signal-integrity wave) to evaluate the EMC of a PCB. Fixing the signal- or power-integrity problems on the card often fixes your EMC problem, as well. You can use time-domain simulations for lower frequencies and smaller physical problems. The key benefit of the time-domain techniques is that they use GPU (graphics-processing-unit) cards, which speed up the math.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">James Stack, training, applications, and consulting manager at Remcom Technology Solutions, reports that adding one GPU speeds solvers by a factor of 30 and stuffing your computer with four GPU cards can speed things up by a factor of 150. David Johns, vice president of technical support and engineering at CST (Computer Simulation Technology), reports that his company’s time-domain solver runs problems 12 times faster with a GPU.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Unfortunately, at higher frequencies, time-domain techniques are not the best way to solve for EM fields. FEM and time-domain field-solver techniques work best for slower signals, while MOM and asymptotic solvers work for faster speeds and larger problems. You are better off using a frequency-based solver in a PC workstation with lots of memory and multiple CPU cores. Companies such as Feko and CST use MLFMM (multilevel- fast-multipole-method) techniques, which solve large problems with less computer power. As the problems become large and must run at frequencies greater than 10 GHz, you must use special solvers that can do asymptotic analysis, which solves for large sets. In some simulations, one physical domain affects another (see sidebar “Multiphysics keeps tabs on your design”).</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Some products, such as those from Cadence, Mentor Graphics, and Zuken, have tools to get electrical and physical information into the simulation software. When you do your PCB design in these vendors’ tools, the vendors provide a complete representation of the PCB-layer stackup and material, allowing their signal-integrity and fieldsolver tools to use this data in their simulations.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Also make sure that point tools can accept your PCB data. CST and Sigrity take databases from Cadence, Mentor, Zuken, and Altium, and these tools and many others accept ODB (open-database)++ PCB fabrication to define the physical configuration and materials in PCBs. Full-wave-simulation vendors, such as SPEAG and 2Comu, are familiar with 3-D databases and can import STEP (Standard for the Exchange of Product Model Data), IGES (Initial Graphics Exchange Specification), DXF, and other mechanical-solid-modeling outputs. Once in the simulation program, the program meshes the solids with algorithms appropriate to the method.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Defining the mechanical shapes and dielectric constants of the physical design is only part of the EMC-analysis problem. When using a time-domain technique, you can just put the proper time-domain waveforms on the ends of the traces. IBIS (I/O-buffer-information specification), a time-domain look-up table of driver-pin waveforms, can describe the rise and fall of a signal on a pin. You also must define the data on the pin; a PBRS (pseudorandom binary sequence) is often adequate for representing the spectral content of the signal on a functional product.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">You can use IBIS-AMI (algorithmic-modeling interface) to define the preemphasis circuits and equalizers in the chips you are using, but it does not define the actual waveforms that will appear when your product is running. Typically, you just use a PBRS into the IBIS-AMI blocks. Meanwhile, your design may have hundreds of traces that might interact.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">S-parameters are the best way to represent the spectral content for the sources of EM noise at high frequencies. An S-parameter representation of a PCB block still does not give you the spectral content that the block will output unless you properly excite the block with signals typical of those that the product will use. Using EM simulations for EMC does give rise to a “chicken-or-egg” problem. Sometimes, the only thing that has the adequate representation of the frequency spectrum being radiated is a working board inside a real case. In that situation, it may make no sense to simulate the problem when you can simply test it, but doing simulations is important. You must know where your simulations deviate from actual results, and doing a correlation between the simulations and real measurements allows you to improve your models, your meshing, or your technique. This approach may not save time for the product you are currently working on, but it can shave months or even years off the development of the next one. Getting results from a Spice simulation that creates a near-field model that you then import to a 3-D solver is a good way to stay in control of your EMC problems.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;"><em><strong>Tools for EM simulation</strong></em></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">No single piece of software can do EMC analysis. You should assemble a suite of software tools to help battle your EMC demons. For example, boardlevel tools can ensure that the signals go where you intend instead of radiating to space. All enterprise-class PCB companies have good field-solver tools to help with signal integrity (Reference 3). Mentor Graphics may be most well-known for its HyperLynx tool, but Cadence, Ansoft, and Zuken also have powerful tools that work on a PCB with hundreds or thousands of traces. SiSoft makes a signal-integrity tool similar to HyperLynx. Sigrity Systems offers its software as a point tool to plug into PCB flows. This tool finds how power- integrity problems and signal-integrity problems relate to each other (see sidebar “SI and power integrity are also important”). Once you have a well-designed PCB, you may then have to approach the problem as if you were an RF-board designer.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">RF-design-software companies Agilent ADS, AWR Microwave Office, Ansoft, Sonnet, CST, and dozens of others can help you deal with the vagaries of EMC analysis. Most of these companies also offer plug-in software, such as the EMPro software in Agilent’s ADS, which performs EM modeling. These tools also account for metal boxes and shields around the circuits and can evaluate the relationship between the electrical and mechanical aspects of your design—an inherent requirement of RF design. RF designers know that their circuits’ performance changes after the cover is on. RF-design tools can model the cooling slots in the case and tell you the amount of radiation coming from them for a given frequency excitation.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Excitation constituting random fields pouring from your PCB as it operates is a more intractable problem, but field-solver companies CST and Ansoft demonstrate how you can solve it. You use time-domain simulations with real waveforms on multiple traces to do a simulation. You then capture a near-field representation of the radiation from the PCB. At a short distance from a source, the electric and magnetic fields do not directly relate, as they do in a wave propagating through space. You then plug this near-field result into a full-wave solver that can calculate the effects of your product’s case, cables, and other mechanical features.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;"><strong><em>Software can't think</em></strong></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Field-solver EM simulations do not provide an EMC panacea. Furthermore, they are not magical genies that can solve a design disaster. Field-solver vendors stress that computer simulations are parts of the entire design process, not some tacked-on afterthoughts that you do as a penance when your product fails FCC testing. You can’t expect a computer simulation to identify every area in which you may have to make improvements. However, if you use and understand the simulations of various parts of your design as it progresses, you will be in better shape when submitting your product for FCC and CE testing. In many cases, the most valuable thing that a computer simulation will do is teach you the nonintuitive behavior of EM fields in a complex product. Playing with the configurations, materials, and shielding will help you understand what is going on, and you can design the product to comply with regulations.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">With signal frequencies in the gigahertz, a finned heat sink on an FPGA acts as a<strong><em> <span style="font-size: large;">phased-array antenna</span></em></strong>, radiating energy in your product. The cooling slots on the case are also phased antennas. Even if you do not have the time or budget to do a full simulation of the electrical signals on the board radiating to a point 3m away, you can still use fullwave simulations. A broadband simulation of the heat sink tells you at which frequencies the sink resonates and the spatial pattern of the resonance. You can also do a broadband excitation of the slotted case. If the frequencies and locations of the heat-sink resonance align with the resonance of the case, those frequencies will cause trouble. The fix may be as simple as rotating the heat sink 90° or changing the spacing of the fins, the slots on the case, or both.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Field-solver programs have steep learning curves, especially for engineers unfamiliar with 3-D simulations. Once you understand the software, you must learn how to import your physical configurations and electrical stimuli. It may seem like an unending task, but once you get a simulation to accurately predict the EMC performance of your product, you will see the attraction of using simulations. They allow you to evaluate things in hours instead of months. They don’t guarantee that your product will pass radiation and immunity tests, but they give you a big head start over companies that simply use “cut-and- try” methods to get their products through FCC and CE approvals. You do testing at the end of the product cycle, when whether you ship the product determines your company’s fortunes.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Smart engineers use software simulations to evaluate EMC in the early phase of the design cycle, moving the risky EMC problems away from the critical product-release phase. They still need to make design and schedule changes but have enough time to efficiently solve the problem without delaying the product’s introduction.</div><br />
<strong>Fuente:</strong> <a href="http://www.edn.com/article/509651-EM_simulation_for_EMC_keeping_a_lid_on_interference.php">http://www.edn.com/article/509651-EM_simulation_for_EMC_keeping_a_lid_on_interference.php</a><br />
<strong>Ver blogger original: </strong><a href="http://nubia-anc.blogspot.com/">http://nubia-anc.blogspot.com/</a><br />
<strong>Materia: CRF</strong>Nubia A. Navarro C.http://www.blogger.com/profile/16124874914747829398noreply@blogger.com0tag:blogger.com,1999:blog-5677235594720330703.post-42949678691833912872010-07-25T18:53:00.000-07:002010-07-25T18:53:49.104-07:00New Antenna From AR Is Approximately 75% Smaller With No Reduction In Key Electrical Performance<div style="text-align: justify;"><strong><em>July 16, 2010</em></strong></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Souderton, PA -- AR RF/Microwave Instrumentation has unveiled a new antenna that represents another advance in antenna technology.</div><div style="text-align: justify;"></div><div style="text-align: justify;"><br />
</div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhiUAURp4d-yKXDuN7w9FH7-Tyzij9ycYD9LPH65xUAzBVF1xvahyphenhyphenyxVKLgl82JqC1f7Mt2lflzj3B0WbakGPjzYo4uD88snRF5A0O1x-3wGRpQL9ALXde4NiWNZtFfXX5LwBw4yIBar-9H/s1600/4.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" hw="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhiUAURp4d-yKXDuN7w9FH7-Tyzij9ycYD9LPH65xUAzBVF1xvahyphenhyphenyxVKLgl82JqC1f7Mt2lflzj3B0WbakGPjzYo4uD88snRF5A0O1x-3wGRpQL9ALXde4NiWNZtFfXX5LwBw4yIBar-9H/s320/4.jpg" /></a></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Model ATR26M6G-1 (26 MHZ – 6 GHz / 5,000 watts) is a wide band, high gain antenna with a proprietary design that combines AR's "bent element" approach with additional innovations. The result is an extremely versatile antenna that provides a size reduction of approximately 75% without sacrificing key electrical performance such as gain and bandwidth. The antenna's size and performance make it uniquely suited for use in both traditional applications and in new compact chambers.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">The ATR26M6G-1 features a reduced profile and extremely low VSWR, making it an excellent choice for high-field-strength immunity testing. The size reduction minimizes field loss that can result from "room loading." The broad frequency range addresses existing RF susceptibility requirements as well as anticipated future developments and is matched to work with AR's "W," "S" and "A" Series RF power amplifiers. The robust design can accommodate the high power levels necessary to generate significant E-fields.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">The ATR26M6G-1, which is tough and durable enough to withstand the rigors of outdoor use, can also be calibrated for RF emissions testing.</div><div style="text-align: justify;"><br />
</div><strong>Fuente</strong>: <a href="http://www.rfglobalnet.com/article.mvc/New-Antenna-From-AR-Is-Approximately-75-Small-0001">http://www.rfglobalnet.com/article.mvc/New-Antenna-From-AR-Is-Approximately-75-Small-0001</a><br />
<strong>Ver blogger original</strong>: <a href="http://nubia-anc.blogspot.com/">http://nubia-anc.blogspot.com/</a><br />
<strong>Materia: CRF</strong>Nubia A. Navarro C.http://www.blogger.com/profile/16124874914747829398noreply@blogger.com0tag:blogger.com,1999:blog-5677235594720330703.post-41096146288720352062010-07-25T18:47:00.000-07:002010-07-25T18:47:41.502-07:00New Antenna Technology<strong><em>Out of sight antennas, Jul 23, 2010</em></strong><br />
<br />
<div style="text-align: justify;">The Yacht Technologies division of Selex Communications, a part of the Finmeccanica group, has announced the launch of their Integrated Antenna Solutions (IAS) to the superyacht market.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Antenna masts are just one aspect of yacht design that are not easy to make aesthetically pleasing to the eye. However, IAS is set to influence the future design of superyachts as the new technology allows for all antenna technology to be concealed within the physical body of the yacht. “Even on the largest superyachts, space for antennas and sensors is limited”, explains John Hodder, Head of SELEX Communications Yacht Technologies. “Both performance and aesthetic considerations influence how and where they can be located. As innovators in superyacht technology, we wanted to bring something to our customers that offers designers the opportunity to create superyachts with clean lines, without limiting performance in any way, IAS offers the ideal solution.”</div><div style="text-align: justify;"><br />
</div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjyM9W0lDkHCTrvT0gVtXuEn5WN12DkVnhDx_-jFXKjNCdTTSgW8trxXg22EuzfkR0ZdfeYc6f0PkVz3KSOSISIpcTcy8jZ7RbDnf7Syua1eYv7215W9maRLGoQPH7efX0542FBv5zwx_cF/s1600/1.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" hw="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjyM9W0lDkHCTrvT0gVtXuEn5WN12DkVnhDx_-jFXKjNCdTTSgW8trxXg22EuzfkR0ZdfeYc6f0PkVz3KSOSISIpcTcy8jZ7RbDnf7Syua1eYv7215W9maRLGoQPH7efX0542FBv5zwx_cF/s320/1.jpg" /></a></div><div style="text-align: justify;"><br />
When asked about this new technology for the industry, James Carley, Senior Designer at Bannenberg & Rowell commented: “It would be great, if they can make it real and make it work.” Carley explains that if a designer were able to shape a single dome so that it worked in harmony with the design of the yacht, it would help the overall look and design of the yacht. The idea of combining all the various satellite and antenna domes into one space would be a great step forward in his opinion, but he is cautious of the idea due to the potential for interference when all the technology is under a single dome.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;"></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhizMFUzxQZKq9cb7fCJH486ylHK8AoE4k8euVgnN2-tIW887HIRnv8pGJRZRXiK-qYAYrgNeEq0KKYIzi4-Zvy52hSUlnCBIFT5Pdp1cMSfbnzSSGI__8ejHvwEV1iWuoL2uDSy_s9FDL5/s1600/2.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" hw="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhizMFUzxQZKq9cb7fCJH486ylHK8AoE4k8euVgnN2-tIW887HIRnv8pGJRZRXiK-qYAYrgNeEq0KKYIzi4-Zvy52hSUlnCBIFT5Pdp1cMSfbnzSSGI__8ejHvwEV1iWuoL2uDSy_s9FDL5/s320/2.jpg" /></a></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiqdhASIV0pwR3bptuEmct45Y_sg2hBkUo5XbgEY85T7dg6NbTwSnk12kLRD8aZWz15TwGJxxfepiooHvHNV-iLla76e-IiKVXT3xj4lphEnHVbpPIZxpSJYNzUVU5qGkXKzMQ0GWx4-8rV/s1600/3.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" hw="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiqdhASIV0pwR3bptuEmct45Y_sg2hBkUo5XbgEY85T7dg6NbTwSnk12kLRD8aZWz15TwGJxxfepiooHvHNV-iLla76e-IiKVXT3xj4lphEnHVbpPIZxpSJYNzUVU5qGkXKzMQ0GWx4-8rV/s320/3.jpg" /></a></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Selex claims that the IAS overcomes such issues as interference between multiple antennas when transmitting and receiving by combining several antennas, operating on different frequencies, into a single aerial without affecting performance. The new technology will allow for the designing of bespoke antennas for covert installation, such as hiding the antenna in the cowling of the yacht.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">“We have considerable experience in IAS across a wide range of platforms”, concludes Hodder. “We have been working closely with designers and shipyards to implement this technology in naval applications for more than a decade, so we can guarantee success.”
</div><div style="text-align: justify;"><br />
</div><strong>Fuente:</strong> <a href="http://www.superyachtdesign.com/news.asp?newsid=442">http://www.superyachtdesign.com/news.asp?newsid=442</a><br />
<strong>Ver blogger original</strong>: <a href="http://nubia-anc.blogspot.com/">http://nubia-anc.blogspot.com/</a><br />
<strong>Materia: CRF</strong>Nubia A. Navarro C.http://www.blogger.com/profile/16124874914747829398noreply@blogger.com0tag:blogger.com,1999:blog-5677235594720330703.post-8878537838795705912010-07-25T18:34:00.000-07:002010-07-25T18:34:58.460-07:00Plasma etch and dep tool maker OEM Group adds AlN film foundry services<div style="text-align: justify;"><br />
</div><div style="text-align: justify;">OEM Group Inc of Gilbert, AZ, USA, which provides equipment to silicon, MEMS, LED, RFID, power device and photovoltaic device makers, has added foundry services to its offerings. Specifically, it is offering high-quality aluminum nitride (AlN) foundry, performed in its applications lab. </div><div style="text-align: justify;"></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Included in the firm’s acquisition in March of the Thin Films and PVD product lines from Tegal Corp of Petaluma, CA, USA, the foundry services use the SFI Endeavor AT PVD (physical vapor deposition) platform to produce piezoelectric AlN films on a variety of 4–6-inch wafers used in surface acoustic wave (SAW), bulk acoustic wave (BAW), FBAR (film bulk acoustic resonator), and micro-electro-mechanical system (MEMS) devices. Equipped with a dual-cathode AC power S-Gun magnetron, the Endeavor AT PVD cluster tool has proven sputter technology that can produce superior film crystallinity, uniformity, and precise stress adjustment, it is claimed. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">OEM Group also participates in customer R&D projects by assisting optimization of devices and technology as well as developing deposition processes suited for specific customer requirements. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">“Performance of AlN-based electro-acoustic devices such as BAW and FBAR filters, oscillators, and resonating sensors is substantially tied to thin-film technology,” says PVD process development manager Valeriy Felmetsger. “Reactive magnetron sputtering is a method of choice enabling formation of AlN films with a high degree of c-axis texture and thus a strong piezoelectric response. In mass production, the most important criteria of advanced reactive sputtering are process stability and repeatability of the film properties from run to run, and independent control of the film properties such as crystal orientation, thickness, uniformity, and stress.” The SFI Endeavor AT PVD system suits the deposition of film stack, two-step deposition, or deposition of single AlN films, it is added. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">“We have widened our breadth of products and services to move beyond tool manufacturing,” says OEM Group president Wayne Jeveli. “Our foundry services are a logical next step given our infrastructure, equipment, and expertise,” he adds. “Our foundry service's success is based on the reliable well developed technology we possess and we know customers can trust; careful analysis by our experts of all technical requirements and precise process adjustments to satisfy these requirements; and our professional reputation based on comprehensive hands-on experience in sputtered films technology.” </div><div style="text-align: justify;"><br />
</div><div style="text-align: left;"><strong>Fuente</strong>: <a href="http://www.semiconductor-today.com/news_items/2010/JULY/OEM_130710.htm">http://www.semiconductor-today.com/news_items/2010/JULY/OEM_130710.htm</a> </div><div style="text-align: left;"><strong>Ver blogger original:</strong> <a href="http://nubia-anc.blogspot.com/">http://nubia-anc.blogspot.com/</a> </div><div style="text-align: left;"><strong>Materia: CRF</strong></div>Nubia A. Navarro C.http://www.blogger.com/profile/16124874914747829398noreply@blogger.com0tag:blogger.com,1999:blog-5677235594720330703.post-57318376970020719962010-07-25T18:29:00.000-07:002010-07-25T18:30:24.070-07:00Affinity Biosensors Selects Innovative Micro Technology (IMT) as Foundry Partner for Volume Production of MEMS Particle Mass Sensor<div style="text-align: justify;"><br />
<br />
Affinity Biosensors and Innovative Micro Technology, Inc. entered into a strategic foundry partnership today for volume production of suspended mass resonator (SMR) MEMS devices enabling particle measurement in fluidic solutions with femtogram resolution. The SMR MEMS devices are the chips that drive Affinity Biosensors’ ARCHIMEDES Particle Measurement System, which won the Gold Award for the Best New Product at Pittcon 2010, and most recently, the 2010 R&D100 Award, recognizing it as one of the most technologically significant new products of the past year. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Originally conceived at Massachusetts Institute of Technology, IMT refined and developed a robust process for volume production, including a key component to this product – sub-mTorr vacuum, wafer-level packaging (WLP) technology. ARCHIMEDES measures a particle as it traverses through a microfluidic channel embedded in a resonating cantilever. The mass is determined by detecting the change in resonant frequency at the time the particle enters the tip of the cantilever. Achieving femtogram resolution requires the cantilever to have a very high Q-factor that is only accomplished by encapsulating the cantilever in high-vacuum wafer level packaging (WLP). </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">”Working with IMT has been a very rewarding experience. I know of no other MEMS foundry with the breadth of facilities and depth of expertise needed to develop the sensors for ARCHIMEDES, and to bring them into production. It is not an exaggeration to say that ARCHIMEDES, and perhaps Affinity Biosensors itself, might not exist without our relationship with IMT,” said Dr. Ken Babcock, CEO of Affinity Biosensors. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">IMT builds some of the most complex MEMS devices in the market today. Incorporating proven technology modules and platforms, such as WLP, through silicon vias, and 3D microfluidics, help to mitigate program risks and achieve production-friendly processes. As a result, IMT’s customer products are reaching the market in ever faster times. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">“Of course, we are always pleased when we can provide a value that enables our customers to achieve true technical differentiation in the market,” stated Dr. John Foster, CEO of IMT. “While the concept of the SMR chip is simple, the technology used to produce these devices is not. We are fortunate to have been able to leverage our standard processes and depth of experience in microfluidics to help shorten the development time of this project and are thrilled to be supporting Affinity Bio in production today.” </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;"><strong>About Affinity Biosensors</strong></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Affinity Biosensors is pioneering ultra high-resolution mass measurement for real-world applications in industrial manufacturing, research, life sciences, and nanotechnology. Affinity Biosensors introduced ARCHIMEDES as a new gold standard in particle metrology, and is working to extend this capability to mass-based cytometry for biological research, biotechnology, and therapeutics. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;"><strong>About Innovative Micro Technology, Inc.</strong></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">IMT is a world leader in the production and development of MEMS devices and is the largest pure-play MEMS foundry in the United States. Established in 2000, IMT develops, manufactures, tests, and supplies products to the RF, biotech/biomed, optical communications, infrared, navigation, and general markets, servicing Fortune 500 companies to startups. For more information on IMT and its services, visit the company website at http://www.imtmems.com. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;"><strong>Contacts</strong></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Innovative Micro Technology</div><div style="text-align: justify;">Theodore Chi, Director of Marketing and Sales</div><div style="text-align: justify;">Tel: 1-805-681-2852</div><div style="text-align: justify;"><a href="mailto:ted@imtmems.com">ted@imtmems.com</a></div><div style="text-align: justify;"><a href="http://www.imtmems.com/">http://www.imtmems.com/</a></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">or</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Affinity Biosensors</div><div style="text-align: justify;">Ken Babcock, CEO</div><div style="text-align: justify;">Tel: 805-455-0181</div><div style="text-align: justify;"><a href="mailto:ken@affinitybio.com">ken@affinitybio.com</a></div><div style="text-align: justify;"><a href="http://www.affinitybio.com/">http://www.affinitybio.com/</a></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;"><strong>Fuente: </strong><a href="http://www.financialpost.com/markets/news/Affinity+Biosensors+Selects+Innovative+Micro+Technology+Foundry+Partner+Volume+Production+MEMS+Particle+Mass+Sensor/3266547/story.html">http://www.financialpost.com/markets/news/Affinity+Biosensors+Selects+Innovative+Micro+Technology+Foundry+Partner+Volume+Production+MEMS+Particle+Mass+Sensor/3266547/story.html</a></div><div style="text-align: justify;"><strong>Ver blogger original:</strong> <a href="http://nubia-anc.blogspot.com/">http://nubia-anc.blogspot.com/</a></div><div style="text-align: justify;"><strong>Materia: CRF</strong></div>Nubia A. Navarro C.http://www.blogger.com/profile/16124874914747829398noreply@blogger.com2tag:blogger.com,1999:blog-5677235594720330703.post-7492353605504215202010-07-25T17:59:00.000-07:002010-07-25T18:00:36.710-07:00Fraunhofer ISIT Selects Rudolph Technologies for MEMS Inspection<div style="text-align: justify;"><br />
</div><div style="text-align: justify;"><strong><em>Rudolph advanced macro inspection system to be used for developing processes for high-volume manufacturing and packaging of inertial MEMS on wafer level.</em></strong></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">FLANDERS, N.J., Jul 12, 2010 (BUSINESS WIRE) -- Rudolph Technologies, Inc. /quotes/comstock/15*!rtec/quotes/nls/rtec (RTEC 8.58, +0.46, +5.67%) , a leading provider of process characterization equipment and software for wafer fabs and advanced packaging facilities, announced that the Fraunhofer Institute for Silicon Technology (ISIT) in Germany has placed an order for an NSX(R) Series Macro Inspection System for advanced MEMS processing. The system will be installed this summer in the state-of-the-art 200 mm MEMS pilot production line at ISIT. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;"></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiCMBbQUGbrUZcSkbeOCDjLU10K6bIV1Jv1qXuJWEuec7zu7TGj0PXPkaVKcLVksv1ZGpppmpW6CRcZYZCeag6ULIpw_yuNYW4w_YMjkuW0hapepYtynf-Ajs5F15AT-M_ZKTpaoWxPriTa/s1600/PR-Logo-Businesswire.bmp" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" hw="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiCMBbQUGbrUZcSkbeOCDjLU10K6bIV1Jv1qXuJWEuec7zu7TGj0PXPkaVKcLVksv1ZGpppmpW6CRcZYZCeag6ULIpw_yuNYW4w_YMjkuW0hapepYtynf-Ajs5F15AT-M_ZKTpaoWxPriTa/s320/PR-Logo-Businesswire.bmp" /></a><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiKFUfVsAEBBDB_NjhCQeVG0_QukVCTIB3xC3StUPRZ2_YuJBpzIMxiX8HtaGKpIbSI1dwMe-deOoqzjJQOcXdqPBTe2csza1s68BXCHWRZJ3lM9_pXU9j2PXyoM3fCGwmqTCOEL85A-vVL/s1600/untitled.bmp" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" hw="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiKFUfVsAEBBDB_NjhCQeVG0_QukVCTIB3xC3StUPRZ2_YuJBpzIMxiX8HtaGKpIbSI1dwMe-deOoqzjJQOcXdqPBTe2csza1s68BXCHWRZJ3lM9_pXU9j2PXyoM3fCGwmqTCOEL85A-vVL/s320/untitled.bmp" /></a></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">"We are pleased to continue working with ISIT on next-generation MEMS processes," said Hartmut Seeger, sales manager for Rudolph in Europe. "ISIT evaluated the NSX System along with several other inspection systems for this application. Acceptance of this tool confirms that the investments we have made to address unique MEMS inspection requirements, including the challenge of wafer handling, are meeting our customers' needs." </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">The ISO 9001:2008-certified production environment at ISIT enables the development of advanced MEMS devices for inertial, RF and electro-optical applications with the required application-specific packaging technology at the wafer level. The functional integration of extremely small features requires automatic defect inspection at small dimensions with high throughput and limited effect on the wafers. Hermetic wafer level vacuum packaging (with integrated getter) requires an inspection tool that is highly flexible in both hardware and software features. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">"Silicon and glass cap wafers are not only fragile, but have deep cavities and sensitive features on both sides of the wafer, requiring a unique wafer handling concept," said Dr. Wolfgang Reinert, team leader-advanced electronic packaging, Fraunhofer ISIT. "The cap wafer inspection results need to be mirrored and interfaced with the ISIT final electrical test equipment for single device traceability and inkless assembly." </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Sascha Muhlmann, MEMS engineer, Fraunhofer ISIT, added, "The capabilities of Rudolph's Discover(R) all-surface defect analysis and data management software on the NSX platform support these tasks during the device development phase and after the technology transfer to MEMS pilot production." </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">The NSX Series is a fast, repeatable macro defect inspection solution used throughout the semiconductor device manufacturing process. Macro defects can be created during wafer manufacturing, probing, bumping, dicing, or by general handling, and can have a major impact on the quality of a microelectronic device. The NSX, specifically designed for back-end manufacturing and often selected by automotive device manufacturers for 100 percent inspection, can handle whole wafers and thinned wafers on film frames. It can quickly and accurately detect yield-inhibiting defects to provide quality assurance and valuable process information. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">With this order from Fraunhofer ISIT, the installed base of Rudolph Technologies' NSX Systems totals over 600 worldwide. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">The Fraunhofer Institute for Silicon Technology (ISIT) works on design, development and production of microelectronic components as well as micro-sensors, micro-actuators and other components for microsystems technology. Further services offered by the institute are analysis and development of technology pertaining to the quality and reliability of electronic assemblies as well as packaging and mounting technology for microsystems, sensors and multichip modules. www.isit.fraunhofer.de </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Rudolph Technologies, Inc. is a worldwide leader in the design, development, manufacture and support of defect inspection, process control metrology, and data analysis systems used by semiconductor device manufacturers worldwide. Rudolph provides a full-fab solution through its families of proprietary products that provide critical yield-enhancing information, enabling microelectronic device manufacturers to drive down costs and time to market. Rudolph offers yield management solutions used in wafer processing and final manufacturing through a family of systems for macro-defect inspection (detection and classification), as well as transparent and opaque thin film measurements. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">The company has enhanced the competitiveness of its products in the marketplace by anticipating and addressing many emerging trends driving the semiconductor industry's growth. Rudolph's strategy for continued technological and market leadership includes aggressive research and development of complementary inspection and metrology solutions. Headquartered in Flanders, New Jersey, Rudolph supports its customers with a worldwide sales and service organization. Additional information can be found on the company's web site at www.rudolphtech.com. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;"><strong>Safe Harbor</strong> </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995 (the "Act") which include demand for Rudolph's products, Rudolph's existing market position and its ability to maintain and advance such position relative to its competitors and Rudolph's expectations about our future bookings and backlog as well as other matters that are not purely historical data. Rudolph wishes to take advantage of the "safe harbor" provided for by the Act and cautions that actual results may differ materially from those projected as a result of various factors, including risks and uncertainties, many of which are beyond Rudolph's control. Such factors include, but are not limited to, delays in shipping products for technical performance, component supply or other reasons, the company's ability to leverage its resources to improve its positions in its core markets and fluctuations in customer capital spending. <br />
<br />
Additional information and considerations regarding the risks faced by Rudolph are available in Rudolph's Form 10-K report for the year ended December 31, 2009 and other filings with the Securities and Exchange Commission. As the forward-looking statements are based on Rudolph's current expectations, the company cannot guarantee any related future results, levels of activity, performance or achievements. Rudolph does not assume any obligation to update the forward-looking information contained in this press release. </div><div style="text-align: justify;"><br />
</div><strong>Fuente</strong>: <a href="http://www.marketwatch.com/story/fraunhofer-isit-selects-rudolph-technologies-for-mems-inspection-2010-07-12?reflink=MW_news_stmp">http://www.marketwatch.com/story/fraunhofer-isit-selects-rudolph-technologies-for-mems-inspection-2010-07-12?reflink=MW_news_stmp</a><br />
<strong>Ver blogger original:</strong> <a href="http://nubia-anc.blogspot.com/">http://nubia-anc.blogspot.com/</a><br />
<strong>Materia: CRF</strong>Nubia A. Navarro C.http://www.blogger.com/profile/16124874914747829398noreply@blogger.com0tag:blogger.com,1999:blog-5677235594720330703.post-88433720715005809272010-07-25T17:50:00.000-07:002010-07-25T17:52:37.551-07:00WiSpry Team Wins Smart Antenna Front End (SAFE) Project<div style="text-align: justify;"><br />
<strong><em>The new $8 million SAFE project aims to revolutionize cellular phone antenna technology.</em></strong><br />
<br />
</div><div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none; text-align: justify;"><div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none;">IRVINE, Calif., July 12, 2010 /PRNewswire via COMTEX/ -- On the heels of last week's announcement of its collaboration with IBM, WiSpry, Inc., the leader in tunable radio frequency (RF) semiconductor products for the wireless industry, today announced that it has won, along with key partners, a four year, $48 million DKK ($8 million USD), Smart Antenna Front End (SAFE) project to be funded by Denmark's High Technology Foundation. WiSpry will work together with Aalborg University (AAU), antenna specialist Molex Interconnect, and chipset leader Infineon Technologies to develop tunable antennas and RF front-ends based on WiSpry's tunable RF technology. To work closely with its partners, WiSpry will be establishing a technical presence in Aalborg, Denmark. <br />
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</div></div><div style="text-align: justify;"><div class="separator" style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none; clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhYVZj60fb_NyP4QABkdD98Qa8yKjX0GoO0DnT4Cxxkn1zHp7wMRvfIkxtwid2h_wFPe3-cCikOw_KptrOJ2fIruNY8zOIKZBRZkBl0iEbEPrJ-fFLQabq6uXxcKqi78SOmLYNQ9AdwiPP-/s1600/PR-Logo-Newswire.bmp" imageanchor="1" style="cssfloat: left; margin-left: 1em; margin-right: 1em;"><img border="0" hw="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhYVZj60fb_NyP4QABkdD98Qa8yKjX0GoO0DnT4Cxxkn1zHp7wMRvfIkxtwid2h_wFPe3-cCikOw_KptrOJ2fIruNY8zOIKZBRZkBl0iEbEPrJ-fFLQabq6uXxcKqi78SOmLYNQ9AdwiPP-/s320/PR-Logo-Newswire.bmp" /></a></div><div class="separator" style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none; clear: both; text-align: center;"><br />
</div><div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none;">The Smart Antenna Front End (SAFE) project's goal is to develop antennas and front-end technology platforms for the next generation of mobile handsets and media devices. SAFE will enable significant reduction in the size and cost of mobile devices while increasing their overall efficiency. </div></div><div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none; text-align: justify;"><br />
</div><div style="text-align: justify;"><div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none;">The SAFE project will be led by professor and antenna specialist Gert Frolund Pedersen at Aalborg University's Department of Electrical Systems. Prof. Pedersen stated, "This will be of enormous importance, not only for cell phones, but eventually for all wireless communications." </div></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">"Traditionally, RF and antenna development has been separate and this has led to suboptimal solutions. In this program we have, for the first time, brought together expertise from both sides. This consortium has the goal of developing specific control, as well as integration technology for both antenna and RF. This can potentially become a part of all mobile phones in the future," said Per Hartmann Christensen from Infineon Technologies. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Morten Christensen from Molex stated, "During the last 10 years, Molex has built up a unique competency in the antenna area. With the SAFE program we, together with the other parties, have an opportunity to think differently and solve the technical challenges that includes the next generation of smart antennas. I expect this consortium will develop the world's best (smartest) smart antenna systems." </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">"Inherently agile radio front-ends will provide tomorrow's mobile devices with peak performance at smaller form factors and lower costs," stated Dr. Arthur Morris, chief technology officer, WiSpry. "Wispry's RF tuning and sensing technologies have been developed specifically to provide wide tunability with high precision and easy integration. We expect the SAFE program to prove feasibility of this revolutionary wireless vision and we are excited to join the world-class team in Aalborg." </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;"><strong>About WiSpry</strong> </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Headquartered in Irvine, Calif., WiSpry is a fabless RF semiconductor company that designs and manufactures RF CMOS integrated circuits and components for leading manufacturers of mobile phones, laptops and wireless data communications products. Utilizing the Company's core competency in RF micro-electro-mechanical systems (RF-MEMS) technology, WiSpry creates revolutionary wireless 'System on Chip' MEMS-based RF architectures, and has recently begun shipping products to a Tier 1 mobile handset manufacturer. WiSpry tunable RF-MEMS devices enable the development of tunable RF front-ends, allowing system designers to achieve the architectural innovation required to meet the growing challenges of mobile communications networks. For more information, visit <a href="http://www.wispry.com/">http://www.wispry.com/</a>. </div><br />
<strong>Fuente</strong>: <a href="http://www.marketwatch.com/story/wispry-team-wins-smart-antenna-front-end-safe-project-2010-07-12?reflink=MW_news_stmp">http://www.marketwatch.com/story/wispry-team-wins-smart-antenna-front-end-safe-project-2010-07-12?reflink=MW_news_stmp</a><br />
<strong>Ver blogger original:</strong> <a href="http://nubia-anc.blogspot.com/">http://nubia-anc.blogspot.com/</a><br />
<strong>Materia: CRF</strong>Nubia A. Navarro C.http://www.blogger.com/profile/16124874914747829398noreply@blogger.com0tag:blogger.com,1999:blog-5677235594720330703.post-73036836596569149732010-07-25T17:41:00.000-07:002010-07-25T17:41:02.555-07:00Design and Development of a Package Using LCP for RF/Microwave MEMS Switches<div style="text-align: justify;"><br />
</div><div style="text-align: justify;"><strong><em>Morgan Jikang Chen, Member, IEEE, Anh-Vu H. Pham, Senior Member, IEEE, Nicole Andrea Evers, Chris Kapusta, Joseph Iannotti, William Kornrumpf, John J. Maciel, Member, IEEE, and Nafiz Karabudak.</em></strong></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Abstract—We present the development of an ultrahigh moisture-resistant enclosure for RF microelectromechanical system (MEMS) switches using liquid-crystal polymer (LCP). A cavity formed in LCP has been laminated, at low temperature, onto a silicon MEMS switch to create a package. The LCP-cap package has an insertion loss of less than 0.2 dB at X-band. E595 outgas tests demonstrate that the LCP material is suitable for constructing reliable packages without interfering with the operation of the MEMS switch. The package also passes Method 1014, MIL-STD-883 gross leak, and fine leak hermeticity tests. Index Terms—Cavities, chip-on-flex, liquid-crystal polymer (LCP), microelectromechanical system (MEMS), microwave, packaging.</div><br />
<div style="text-align: center;"><strong>I. INTRODUCTION</strong></div><br />
<div style="text-align: justify;">PACKAGING is a critical part in bringing the RF microelectromechanical system (MEMS) into application at an affordable cost. MEMS switches are very sensitive to contamination and must be packaged with hermetic or near-hermetic seals in inert noble gas environments. These switches require hermetic packaging to prevent against contaminating particles and moisture. Invasion of particles into the MEMS device can cause the switch to be wedged open, stuck closed where the particle aggravates stiction, or simply degrade performance by acting as a resistive material.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">A number of solutions are available for packaging MEMS switches. Several techniques used by industry to package MEMS devices include epoxy seals, glass frit, glass-to-glass anodic bonding, and gold-to-gold bonding. These techniques face two main problems. First, organic materials outgas inside the MEMS cavity during the bonding process due to wetting compounds in the glass, gold, or epoxy layers.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">This contamination detrimentally affects the MEMS switch reliability. Second, to achieve a good seal, most bonding processes utilize high temperatures (300 C–400 C) that can degrade MEMS structures. Furthermore, available hermetic packages and ceramic/glass feed-throughs have significant parasitic losses at microwave frequencies, can be expensive, and add significant weight to a system. Packaging MEMS switches into an organic module, in which compact multilayer substrates house active and passive components present even more challenges. Although multilayer chip-on-flex modules using Kapton films are a proven technology for high-density packaging of microwave modules,2 3 Kapton is found to be incompatible with RF MEMS switch packaging due to its high moisture absorption, high out-gassing characteristics, and the need to use high outgassing epoxies for lamination.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">In this paper, we present the development of an ultrahigh moisture-resistant package for RF MEMS switches in chip-on-flex modules using liquid-crystal polymer (LCP). We have developed a lamination process to adhere LCP onto silicon to form an enclosure for MEMS. Using multilayer flex and laser-drilled vias, the first level interconnect parasitic losses are negligible at X-band. The microwave measurements demonstrate that the LCP-package has less than 0.2-dB insertion loss and maintains the return loss of a switch to greater than 20 dB. The LCP MEMS package passes the E595 out-gassing test and Method 1014, MIL-STD-883 gross leak, and fine leak hermeticity tests.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Section II provides a brief review of multilayer organic modules, an introduction to LCP, and processes to create the LCP MEMS package. Section III demonstrates the experimental results of peeling strength tests, out-gassing tests, hermeticity tests, and lamination process evaluation. Section IV provides detailed analysis of the electrical performance of a package. Section V demonstrates the electrical performance of a packaged</div><div style="text-align: justify;">RF MEMS switch in an LCP enclosure.</div><br />
<div style="text-align: center;">II. PACKAGE TOPOLOGY</div><br />
<div style="text-align: justify;">The multilayer organic multichip module (MCM) is a potential candidate for integrating a system-in-package (SiP) at microwave and millimeter-wave frequencies. This technology has been utilized to package high-peed memory integrated circuits (ICs) and transceiver modules for communications. In 1998, Butler et al. had attempted to use thisMCMtechnology to package MEMS devices. However, the multilayer Kapton is not suitable for hermetic packaging of MEMS. In order to provide hermetic packaging of an RF MEMS switch, we investigate the feasibility of LCP as a multilayer interconnect layer in place of Kapton.<br />
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<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhsiNcjbC3ur3Zx-5nlI36fekIzJjTKijH4dveEMlb2pQM0qd3t5YUxWMowYoD26W-qvOb1gSrLvnW_F0x38rRTod-sdAYSxFK2PSmTYQqkbLgD4vkLM56wLgOf3ZSTlB4ljlAqIDw0CBD-/s1600/I1.bmp" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" hw="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhsiNcjbC3ur3Zx-5nlI36fekIzJjTKijH4dveEMlb2pQM0qd3t5YUxWMowYoD26W-qvOb1gSrLvnW_F0x38rRTod-sdAYSxFK2PSmTYQqkbLgD4vkLM56wLgOf3ZSTlB4ljlAqIDw0CBD-/s320/I1.bmp" /></a></div></div><div style="text-align: justify;">LCP is an emerging low-cost dielectric material that is commercially available as single sheets or laminated substrates that have low moisture absorption (equivalent to glass). Table I compares the basic properties of LCP with Kapton. LCP can be manufactured to have different properties including a coefficient of thermal expansion (CTE) range from (8 -17).10^-6/ K and a glass transition temperature Tg from 280 C to well over 350 C. The use of low and high melting-point temperature LCP allows for layer-to-layer lamination processes without the use of adhesive materials. The main advantages of LCP compared to other organic substrate materials are low moisture absorption, low coefficient of hydroscopic expansion (CHE), excellent barrier properties, and adjustable CTE through thermal treatment processes. Moreover, LCP shows a very low dielectric constant and loss factor, over the frequency range of 1 GHz up to 110 GHz [11]. This unique combination of excellent electrical characteristics, excellent mechanical properties for harsh environment operation, and economical considerations make LCP a serious candidate for all MCM, SiP, and advanced packaging technology.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">We have developed a process to laminate LCP onto silicon to form an enclosure for packaging an RF MEMS switch without the use of adhesives. One of the advantages of lamination is the low-temperature processing (below ~315 C), as compared to metallic or glass bonding ( ~400 C). Fig. 1 demonstrates our process flow for laminating LCP on silicon. The process starts with a bare 2-mil-thick LCP that has copper on one side. The copper serves as the roof of the cavity drilled in the LCP film. </div><div style="text-align: justify;"> </div><div style="text-align: justify;">The MEMS cavity is formed in the 2-mil-thick LCP using laser ablation to the copper lid. The ash is removed using isopropyl alcohol solvent. This cavity acts as a hermetic enclosure formed by the copper lid and LCP walls. The laser ablation is a convenient method to pattern the chemically stable LCP to provide very accurate vertical sidewalls. The single-sided copper-clad LCP film with the laser-drilled cavity is laminated onto an exposed and released silicon switch. The commercially available LCP films have a melting temperature from 240 C to 315 C, which, for robustness of process, is thermally well below any temperature that may impact the MEMS switch. Inert gas can be injected into the cavity to help improve the switch performance during the lamination process. Excellent lamination results have been obtained over a large range of pressures. Through our processing, we obtain 1 m of accuracy using conventional flipchip die bonding equipment. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Once the lamination is completed, square microvias 100- m long along each side and interconnects are formed on the LCP layer. The fabrication of vias and metal interconnects is similar to the process reported in Fig. 2 shows the three-dimensional (3-D) diagram of the LCP packaged RF MEMS switch, and Fig. 3 shows the actual packaged RF MEMS switch prototypes.<br />
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</div><div align="justify" class="separator" style="clear: both; text-align: center;">III. PROCESS AND PACKAGE EVALUATION</div><br />
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In order to demonstrate that LCP may be used as a package material, tests have been performed to address out-gassing, adhesion strengths, structural integrity, and hermeticity. <br />
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<strong>A. Out-Gassing Tests</strong> <br />
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Out-gassing is a major barrier in using polymer materials for packaging RF MEMS. During the processing of polymer in RF MEMS packaging, polymer materials tend to release gas particles that would degrade the reliability of the RF MEMS switch. The ASTM-E 595–93 (1999) tests were employed to evaluate the out-gassing characteristics of LCP materials.<br />
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These tests were conducted by measuring mass changes at 125 C under vacuum for 24 h. Results are given as total mass loss (TML), collected volatile condensable materials (CVCMs), and water vapor regain (WVR). TML is the percent difference of mass measured before and after the test. CVCM is the percentage of condensed mass measured on a collector plate over the initial specimen mass. WVR is calculated by placing the measured specimens through 50% relative humidity at 23 C for 24 h, and the value is given as the percentage of increase of specimen mass before and after humidity conditioning.<br />
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Historically, a TML of 1% and a CVCM of 0.1% are the maximum levels for materials used in spacecraft applications. As seen from Table II, the experimental results demonstrate that the LCP has passed the out-gassing tests and satisfies the requirements for spacecraft applications. More importantly, even though LCP is a polymer material, it has negligible out-gassing and is suitable for RF MEMS switch packaging. <br />
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<strong>B. Adhesion and Package Integrity</strong><br />
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One of the advantages of LCP films is that they are able to adhere to other materials without the use of external adhesives in a lamination process. This feature not only simplifies the packaging process, but also reduces the electrical loss that is associated with lossy adhesive materials. Out of reliability concerns, adequate adhesion strengths are required because either a weak LCP-to-silicon or a weak LCP-to-metal bond could prevent vias from being formed and contacted correctly. <br />
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We have conducted a pulling test to evaluate the adhesion strength of LCP on silicon using a Chatillon pull tester. Fig. 4 shows a cross section of the test structure and how the experiment has been conducted. The experimental results demonstrate that the adhesion of LCP onto Si is more than 3 lbs/in. A comparison of sputter adhesion strengths is provided in Fig. 5, which indicates that the 3-lbs/in adhesion strength is adequate to provide a reliable enclosure. A photograph of a test sample after being subjected to a peel test is shown in Fig. 6. It is interesting to note that even though the Cu/LCP was being separated from Si, it was actually the Cu/LCP interface that came apart first, which attests to the high lamination strength between LCP and silicon.<br />
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<strong>C. Structural Integrity</strong><br />
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From the peel testing, we discovered that optimal lamination strength actually occurred over a temperature range around the melting temperature ( ), as opposed to simply being above a certain threshold value. If the lamination temperature was too low, the lamination strength would be poor. Conversely, if the lamination temperature was too high, then widely varying nonuniform lamination strengths occurred along the interface of LCP and silicon. At the extremes, nonuniform lamination at the interface gave the appearance of good bonds speckled in regions of generally poor lamination. Under optimal conditions, our peel tests show LCP-to-silicon lamination to be in excess of 10 lbs/in. <br />
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Fig. 7(a) shows an open rectangular hole in LCP laminated on a silicon substrate that has interdigitated fingers. This rectangular hole is the same size as the cavity used in the MEMS switch enclosure. Fig. 7(b) shows the cross section of the laminated LCP onto Si. As can be seen from Fig. 7(a), after the lamination, the LCP has reflowed and altered the original shape of the sharp rectangular hole. The width of the rectangular hole is 200 m. The reflow is measured to be less than 5 m at the midpoint of the cavity sidewall and 25 m at the corners (noncritical features).<br />
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<strong>D. Hermeticity Tests</strong><br />
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It is well known that polymer materials are usually unsuitable for hermetic packaging because of their high permeabilities, which cause failure during fine leak testing. In order to establish that LCP would be viable for hermetic enclosures, hand calculations are performed based on referred data. LCP has been reported to have a permeability of 2.19 10 cm s for helium in LCP. This value may be compared to the hermetic shielding material Corning 7740 glass in helium, which has a leak rate of 8.5 10 cm s. Package hermeticity is quantitatively analyzed by using the diffusion leak rate closed-form approximation equation Leak rate (1) where is the permeability, is the exposed package area, is the pressure difference, and is the package wall thickness.<br />
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Using a permeability of 2.19 10 cm s for helium in LCP, an exposed area of 0.22 mm , an effective wall thickness of 300 m, and pressure as specified for testing the package with 7.5 10 mm cavity volume, the leak rate is estimated to be 6.424 10 atm cm s. This value is significantly below the cutoff condition required by Method 1014, MIL-STD-883. <br />
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Gross and fine leak hermetic testing has been performed on five LCP-packaged MEMS switches at Six Sigma.4 These parts are fully functional with both dc and RF via connections. The gross and fine leak tests evaluate the hermetic properties of the LCP packages in accordance with Method 1014, MIL-STD-883. Gross leak is generally indicative of structural failure, while fine leak more generally detects contamination pathways by bulk diffusion mechanisms through materials. Gross-leak testing is performed under 60 pounds per square inch guage relative to atmosphere (PSIG) of perfluorocarbon fluid for 125 min and immediately vacuumed under 5 torr for 30 s. The parts are then submerged in a bubble tester and visually inspected for leaks, as indicated by the appearance of any bubbles from the parts. Fine leak testing is performed under 125 min, 60 PSIG helium soak, followed by a 5-torr vacuum for 1 min. The experimental results demonstrate that our packages have passed the gross and fine leak tests in accordance with Method 1014, MIL-STD-883. Due to the small volume size of our package ( 0.06 mm ), standard detection methods may not be capable of measuring the species inside the cavity. Hence, it is questionable if Method 1014, MIL-STD-883, which is the current standard test, can provide conclusive results on hermeticity for small-volume packages.<br />
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<div style="text-align: center;"><strong>IV. ELECTRICAL PACKAGE DESIGN AND SIMULATIONS</strong></div><br />
In order to evaluate the effects of the package on RF MEMS switches, full-wave electromagnetic simulations have been conducted using Ansoft High Frequency Structure Simulator (HFSS) software that employs a finite-element method. The basic structure for studying insertion loss and return loss includes a bare microstrip transmission line on silicon with a bulk conductivity S m. This structure is considered as an unpackaged device, shown in Fig. 8(a). The bare microstrip line is then packaged in LCP ( , ) with a 2-mil height cavity capped by a copper lid, as shown in Fig. 8(b). Copper vias 100 m by 100 m with 5- m-thick walls form the first-level interconnect. Each metal layer is also 5- m thick.<br />
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The chip is 3000 m by 3000 m. Agilent’s Advanced Design System (ADS) LineCalc, which uses close-form equations for calculating impedance and transmission-line geometry, is employed to determine the width of microstrip lines on 254- m-thick Si. The widths of 50- and 80-microstrip lines (unpackaged) are found to be 197 and 50.7 m, respectively. In the packaged simulation, the microstrip section feeding to the coplanar waveguide is deembedded at the port.<br />
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Fig. 9 shows the simulation results of the unpackaged and packaged microstrip lines. When the 80- microstrip line is packaged with a 2-mil-high metal lid, the characteristic impedance is tuned down closer to 50 . In this case, the return and insertion losses of the packaged 80- microstrip lines improves from 13 to 25 dB and from 0.76 to 0.42 dB, respectively, at 10 GHz. The insertion and return losses of the 50- microstrip line worsens from 0.581 dB unpackaged to 0.624 dB packaged and from 24.1 dB unpackaged to 20.6 dB packaged, respectively at 10 GHz.<br />
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Table III compares simulation results of unpackaged and packaged 50- and 80- microstrip lines in 1- and 2–mil-high metal lids. High characteristic impedance microstrip lines are tuned closer to 50- transmission lines when they become striplines with 1- and 2-mil high metal lids. The capacitance per unit length of the striplines increases, which, in turn, decreases the characteristic impedance. This phenomena is described by the well-known equation for characteristic impedance. <br />
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In our research, the MEMS switch has been designed to have a high characteristic impedance ( 80 ) without a package. Hence, we expect that the package will improve the matching of the device to a 50- system. For mechanical robustness, we have chosen a 2-mil-high cavity. An equivalent-circuit model for the microvia interconnect has been developed from simulations using the Sonnet Software that employs the method of moments. This model targets the -band to understand the switch performance. The interconnect model is shown in Fig. 10 to have fF, pH, and models the capacitance between the via to the surrounding ground, and models the inductance associated with the narrow via constructed through the LCP thin film from the outer package to the metal trace on chip-parameters are measured from a packaged thru line.<br />
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<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiVvvA8RklYNXPzHPq1ldIXqoZM2bY8MHZDJJ_wf6k8XVI-bygdgdcnv65t2_xrFQFULTEo3Mgau1q7TfX1nsrBYl5dPhR_yPTfXyMQADdZpYq0WuR9aK2nvifdcLFAXzJpbZyBmypSFX0q/s1600/I8.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" hw="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiVvvA8RklYNXPzHPq1ldIXqoZM2bY8MHZDJJ_wf6k8XVI-bygdgdcnv65t2_xrFQFULTEo3Mgau1q7TfX1nsrBYl5dPhR_yPTfXyMQADdZpYq0WuR9aK2nvifdcLFAXzJpbZyBmypSFX0q/s320/I8.JPG" /></a></div><br />
An analytical method (ADS) is used to deembed all elements in the path other than the interconnect using the technique shown in. Fig. 11 compares modeled and measured -parameters of the transition. This is an agreement to 0.02 dB between model and measurement insertion losses at 10 GHz, which is our frequency of interest. Model and measurement both show less than 0.07-dB insertion loss per package transition at 10 GHz. Return loss shows agreement to less than 4-dB difference between modeled and extracted measurement. This lumped circuit strictly models the via interconnect. When devices are packaged, the interconnects and the additional copper over the packaged device together can cause tuning effects.<br />
<br />
<div style="text-align: center;"><strong>V. MEASURED RESULTS</strong></div><br />
S-parameter measurements have been performed with a Cascade probe station, an Agilent PNA E8364B network analyzer, and Picoprobe coplanar-waveguide probes. A load-reflect-match (LRM) calibration was performed to establish the reference planes to be at the RF probe tips. A dc probe is used to electrostatically bias the switch on with 90 V. The measured results of the LCP packaged switch in the closed state for insertion loss are provided in Fig. 12 over the -band region and plotted up to 18 GHz. Our packaged switches show a total insertion loss of 0.45 dB at -band due to the low-loss LCP material, microvias, and excellent shielding. This includes the additional 0.07 dB loss per interconnection at the input and output with 0.3 dB being attributed to the MEMS switch at -band. In addition, the measured return loss is better than 25 dB. The metal cap of the package tunes the characteristic impedance of the switch closer to 50 . Hence, the return loss of the packaged switch is improved to less than 25-dB return loss.<br />
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<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg6F4Gj8thCE8EYzEwPWRKp5oIReIm1fC67dsLhVZLuzfk4nv-gQeLXWuvUHQ9q7Q2OXXIuSOszU-cOJMxmMa5yQZebPELL25-9lQhukYLa2GFH0L6r1OyLM74fHarB3yqJ4UGqpVNQMsXs/s1600/I9.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" hw="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEg6F4Gj8thCE8EYzEwPWRKp5oIReIm1fC67dsLhVZLuzfk4nv-gQeLXWuvUHQ9q7Q2OXXIuSOszU-cOJMxmMa5yQZebPELL25-9lQhukYLa2GFH0L6r1OyLM74fHarB3yqJ4UGqpVNQMsXs/s320/I9.JPG" /></a></div><br />
The -parameters of the packaged MEMS switch had also been measured in the open or off states (0 V \#\bias). Fig. 13 shows the measured -parameters of the off-state switch. The measured isolation of the packaged switch is 15 dB, which remains relatively the same as the unpackaged switch to within 1 dB.<br />
<br />
Since the particular switches we use had been optimized for an 80- characteristic impedance system, rather than a 50- system, the isolation is a better metric of the packaging.<br />
<div style="text-align: center;"><strong>VI. CONCLUSION</strong></div><br />
This paper has successfully demonstrated an ultrahigh moisture-resistant RF MEMS switch enclosure using LCP. Simulations show that the entire package introduces miniscule electrical degradation to the overall circuit performance. Insertion loss of the LCP packaged switch is roughly 0.5 dB at -band with return loss greater than 25 dB and isolation loss of 14 dB.<br />
<div style="text-align: center;"><br />
</div><div style="text-align: center;"><strong>ACKNOWLEDGMENT</strong></div><br />
The authors wish to acknowledge the collaborative work between the Microwave Microsystems Laboratory, University of California at Davis, the General Electric Global Research Center, Niskayuna, NY, Radant MEMS Inc., Stow, MA, and Lockheed Martin Commercial Space Systems, Newtown, PA.<br />
<br />
<strong>Fuente</strong>: <a href="http://www.ece.ucdavis.edu/mml/papers/J11.pdf">http://www.ece.ucdavis.edu/mml/papers/J11.pdf</a><br />
<strong>Ver blogger original</strong>: <a href="http://nubia-anc.blogspot.com/">http://nubia-anc.blogspot.com/</a><br />
<strong>Materia: CRF</strong></div>Nubia A. Navarro C.http://www.blogger.com/profile/16124874914747829398noreply@blogger.com0tag:blogger.com,1999:blog-5677235594720330703.post-41531824803609779852010-06-27T11:19:00.000-07:002010-06-27T11:20:19.443-07:00Multifunction antenna modules remain strong<div style="text-align: justify;"><br />
<strong><em>GPS antenna modules lead supply of application-specific models, with Bluetooth units expected to rise in coming months.</em></strong></div><br />
<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiYMxcpxa_Bw8xvQkh8B7nbXXUw9X3jUg6X8U1N9IU8cm7JyJYBrlL5QkbYUO8XHgIMKtGONw8cK1vHzVaA4KelzePYh4omL6mysnbmCi38RC1E8t3TTaGsMxSVA2yrnxVpeMA8sTAUlmZs/s1600/i9.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" ru="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiYMxcpxa_Bw8xvQkh8B7nbXXUw9X3jUg6X8U1N9IU8cm7JyJYBrlL5QkbYUO8XHgIMKtGONw8cK1vHzVaA4KelzePYh4omL6mysnbmCi38RC1E8t3TTaGsMxSVA2yrnxVpeMA8sTAUlmZs/s320/i9.jpg" /></a></div><br />
<div style="text-align: justify;">Versions combining more than two functions and technologies remain a major trend in Taiwan’s antenna module industry. GSM+GPS variants, in particular, are the mainstream. Some designers offer Wi-Fi+Bluetooth units for laptops.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Enterprises adopt several wireless protocols, including RF, Bluetooth, GSM, GPS, Wi-Fi and RFID. Applications are diverse, covering mobile phones, computer networking, navigation, digital broadcasting, medical appliances and industrial instruments. The bullish communications sector is currently one of the main growth catalysts. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Most suppliers concentrate on one or several segments, allowing buyers to source products by target use. GPS, Bluetooth, Wi-Fi and RFID are the top choices, with the first leading design work at present. The popular adopters are personal navigation devices, automatic vehicle locators and trackers. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Bluetooth antenna modules are forecast to be the next main trend. Taiwan makers began developing such variants as the technology gained ubiquity in audio and data transmission in consumer electronics. The target sectors are mobile phones, notebook PCs, A/V equipment, data collectors, digital cameras and printers.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Being a highly R&D-centric industry, manufacturers emphasize OEM and ODM capability. They are leveraging product design and development expertise, which many said is their core advantage over mainland China competitors.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Broadening the RF bandwidth compatibility and increasing gain and sensitivity are part of makers’ R&D agenda. EMI and RFI reduction is likewise highlighted. Some enterprises are introducing variants with protection against dust and water.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;"><em><strong>Note:</strong></em> All price quotes in this report are in US dollars unless otherwise specified. FOB prices were provided by the companies interviewed only as reference prices at the time of interview and may have changed. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;"><strong><em>Disclaimer:</em></strong> All product images are provided by the companies interviewed and are for reference purposes only. Those product images featuring products with trademarks, brand names or logos are not intended for sale. We, our affiliates, and our affiliates' respective directors, officers, employees, representatives, agents or contractors, do not accept and will not have any responsibility or liability for product images (or any part thereof) which infringe on any intellectual property or other rights of a third party. </div><div style="text-align: justify;"><br />
</div><strong>Fuente:</strong> <a href="http://www.electroniccomponents.globalsources.com/gsol/I/Antenna-module/a/9000000109932.htm">http://www.electroniccomponents.globalsources.com/gsol/I/Antenna-module/a/9000000109932.htm</a><br />
<div style="text-align: left;"><strong>Ver blogger original</strong>: <a href="http://nubia-anc.blogspot.com/">http://nubia-anc.blogspot.com/</a></div><div style="text-align: left;"><strong>Materia: CRF</strong></div>Nubia A. Navarro C.http://www.blogger.com/profile/16124874914747829398noreply@blogger.com0tag:blogger.com,1999:blog-5677235594720330703.post-5012155783339108802010-06-27T11:00:00.000-07:002010-06-27T11:05:49.479-07:00Phased Array technology: concepts, probes and applications<div style="text-align: justify;"><br />
</div><div style="text-align: center;"><strong>Abstract </strong></div><div style="text-align: justify;"></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Over the last few years, piezocomposite materials have enabled a new ultrasound probe technology to be developed for the Non-Destructive Testing of materials: Phased Array probes. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">These probes, made up of a large number of simple probes organized in linear, annular, circular or matrix arrays, allow electronic scanning, focusing and deflection to be carried out. These different concepts will be presented, as well as their associated benefits in terms of performance, flexibility, speed and feasibility of certain inspections.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Different applications that have implemented this technology will also be presented, with details about the particular probes used. Through these applications, the benefits of phased array technology for many fields will be highlighted, including the nuclear, aeronautical and in-line testing industries.</div><div style="text-align: justify;"><br />
</div><div style="text-align: center;"><strong>Introduction</strong></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">A certain number of industries requiring advanced means of Non-Destructive Testing, such as the nuclear, aeronautic or in-line testing industries, constantly seek improvements in the performance of their monitoring systems. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">The most common requests concern an increase in productivity, reduction in the size of untested areas and improvements in detection and sizing performance.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">For the last ten years, Imasonic has responded to these needs by designing and developing transducers based on Phased Array technology.</div><div style="text-align: center;"><br />
</div><div style="text-align: center;"><strong>The Phased Array concept</strong></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">The Phased Array concept is based on the use of transducers made up of individual elements that can each be independently driven. These probes are connected to specially-adapted drive units enabling independent, simultaneous emission and reception along each channel. These units should also be able to effect, during both emission and reception, the different electronic time delays for each channel. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">For some applications implementing electronic scanning, not all the elements of the probe are used simultaneously. In this case, the drive unit uses dynamic multiplexing to distribute the active elements among the elements of the transducer.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;"><strong><em>Electronic scanning</em></strong></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Electronic scanning, illustrated in figure 6, consists of moving a beam in space by activating different active apertures in turn, each one made up of several elements of a phased array probe.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">It allows a mechanical scanning axis to be replaced electronically.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">In general, this concept is used for in-line testing of plates, bars or tubes, and can also be used for inspecting welds.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;"><strong><em>Electronic focusing</em></strong></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Electronic focusing, shown in figure 7, is based on the use of electronic delays applied during emission and reception along each of the channels of the probe. These delays have an effect similar to that of a focusing lens and enables focusing to different depths. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Electronic focusing allows only one phased array probe to be used where several single-element probes with different focal distances would be necessary. The most common applications are heavy plates inspection. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;"><em><strong>Electronic deflection</strong></em></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Electronic deflection, illustrated in figure 8, uses delay laws for electronic focusing. In this case, they are calculated to give the emitted beam an angle of incidence which can be varied simply by modifying the delay law (all the delays applied to each of the concerned channels).</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Electronic focusing enables only one probe to be used for inspections traditionally requiring several probes working at different angles. In addition, it allows the beam to be deflected without using a wedge, allowing parts to be inspected from very small spaces.(3)</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Electronic scanning, focusing and deflection can be combined to resolve applications such as the inspection of welds or tubes. Examples will be dealt with in the paragraph "Examples of applications" below.</div><div style="text-align: justify;"><br />
</div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh2QDzOYXUzv3rGx_nSnUPpZSW4SaQyoyGpsqS0-XMkdcRPEYaBrl0TBNsQQzsjsIzlpJlJRjCIMt3pw09LlXVBhQW_F9Fc6ZbWvXVMv_umPFUucXpXp09RymTAiUAgYq1AVt7EmFT-aP2d/s1600/i8.gif" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" ru="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh2QDzOYXUzv3rGx_nSnUPpZSW4SaQyoyGpsqS0-XMkdcRPEYaBrl0TBNsQQzsjsIzlpJlJRjCIMt3pw09LlXVBhQW_F9Fc6ZbWvXVMv_umPFUucXpXp09RymTAiUAgYq1AVt7EmFT-aP2d/s320/i8.gif" /></a></div><div class="separator" style="clear: both; text-align: center;"><em><strong><span style="font-size: x-small;">Fig 6: Diagrammatic view of electronic scanning: groups of elements are successively activated to move the beam along the transducer.</span></strong></em> </div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiPhBQNM8uMRz_KSp6Wr0cW-0NgUYpaSw9cWqb-ZMqgkFdUcT8oYY-9gIdjwx_mEqoJ4CSFJ6sFmkEOYoCQ75yhjKw_nlQi0XKLwrI1uuKeqiM7iJdP94WuDSED5RIDeUL-CaEZt4Q9gLfA/s1600/i1.gif" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" ru="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiPhBQNM8uMRz_KSp6Wr0cW-0NgUYpaSw9cWqb-ZMqgkFdUcT8oYY-9gIdjwx_mEqoJ4CSFJ6sFmkEOYoCQ75yhjKw_nlQi0XKLwrI1uuKeqiM7iJdP94WuDSED5RIDeUL-CaEZt4Q9gLfA/s320/i1.gif" /></a></div><div class="separator" style="clear: both; text-align: center;"><em><strong><span style="font-size: x-small;">Fig 7: Diagrammatic view of electronic focusing: electronic delay laws are applied (left) to focus the beam.</span></strong></em> </div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjGkKr0bvUmCvBHTd9jhtZvNI8a2b-DFzM4bE5ju21Uqr3u_uYiAVkSB6WazCM1UlyahnAbR1px2pSm2h6bnck0PysfbkdpL-dCNNiy1z08ITcTKi2I9fCvSBYlRYleGGgkLmACZnQyDt7C/s1600/i7.gif" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" ru="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjGkKr0bvUmCvBHTd9jhtZvNI8a2b-DFzM4bE5ju21Uqr3u_uYiAVkSB6WazCM1UlyahnAbR1px2pSm2h6bnck0PysfbkdpL-dCNNiy1z08ITcTKi2I9fCvSBYlRYleGGgkLmACZnQyDt7C/s320/i7.gif" /></a></div><div class="separator" style="clear: both; text-align: center;"><strong><em><span style="font-size: x-small;">Fig 8: Diagrammatic view of electronic deflection: electronic delay laws are applied (left) to deflect the beam.</span></em></strong> </div><div class="separator" style="clear: both; text-align: center;"><br />
</div><div style="text-align: center;"><strong>Phased array probes</strong> </div><div style="text-align: justify;"></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Phased array technology requires the use of multi-element probes with variable geometry, but must also meet certain criteria:</div><div style="text-align: justify;"><br />
</div><ul><li><div style="text-align: justify;">Elements must be able to be driven individually and independently, without generating vibration in nearby elements due to acoustic or electrical coupling. </div></li>
<li><div style="text-align: justify;">The performance of every element must be as close as possible in order to ensure the construction of a homogeneous beam.</div></li>
</ul><div style="text-align: justify;">Imasonic, thanks to its Piezocomposite 1-3 technology (1) and to its multi-element probe construction technology, designs and manufactures probes that meet these two criteria (2).</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Figure 2 shows the different possible geometries of the multi-element probes described below.</div><div style="text-align: justify;"><br />
</div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh92cnXr8Tf4vOBV4g5PXHPfQV3f_JSUBBSn8kBrs6QWHRps-d470wkhvEtMvbdb251_5dNwkZGdWn9ihbLsidi7d-H3qKQMDR8NKv49zVqYlpUPtNvFW0SxszjUQBn6YMijZrOTXwGEg4U/s1600/i2.gif" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" ru="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh92cnXr8Tf4vOBV4g5PXHPfQV3f_JSUBBSn8kBrs6QWHRps-d470wkhvEtMvbdb251_5dNwkZGdWn9ihbLsidi7d-H3qKQMDR8NKv49zVqYlpUPtNvFW0SxszjUQBn6YMijZrOTXwGEg4U/s320/i2.gif" /></a></div><div class="separator" style="clear: both; text-align: center;"><em><strong><span style="font-size: x-small;">Fig 2: Examples of geometries of phased array transducer elements:</span></strong></em></div><div class="separator" style="clear: both; text-align: center;"><em><strong><span style="font-size: x-small;">1. Linear array</span></strong></em></div><div class="separator" style="clear: both; text-align: center;"><em><strong><span style="font-size: x-small;">2. Annular array with uniform pitch (non constant surfaces) </span></strong></em></div><div class="separator" style="clear: both; text-align: center;"><em><strong><span style="font-size: x-small;">3. Matrix arrays (checkerboard and sectored rings) </span></strong></em></div><div class="separator" style="clear: both; text-align: center;"><em><strong><span style="font-size: x-small;">4. Circular array</span></strong></em></div><div style="text-align: justify;"><br />
<em><strong>Linear array probes</strong></em> </div><div style="text-align: justify;"></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">These probes are made up of a set of elements juxtaposed and aligned along an axis. They enable a beam to be moved, focused, and deflected along a plane. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;"><strong><em>Annular array probes</em></strong></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Annular array probes are made up of a set of concentric rings. They allow the beam to be focused to different depths along an axis. The surface of the rings is in most cases constant, which implies a different width for each ring. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;"><em><strong>Circular array probes</strong></em></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">These probes are made up of a set of elements arranged in a circle. These elements can be directed either towards the interior, or towards the exterior, or along the axis of symmetry of the circle. In the latter case, a mirror is generally used to give the beam the required angle of incidence (see figures 3 and 4). </div><div style="text-align: justify;"><br />
</div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjIeh8aHVzhryBooHEmuAp6GQSw2D3LTE4s0K77jcofREajfnwV7OZtiT2Kb3vd5yDzlIebiuyo01tSHC2HLMshUIUBr6VJXYkfyn3g8m5nrPR-z4S7LE82b2BnClq80EaPKnq__6w_VxkR/s1600/i3.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" ru="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjIeh8aHVzhryBooHEmuAp6GQSw2D3LTE4s0K77jcofREajfnwV7OZtiT2Kb3vd5yDzlIebiuyo01tSHC2HLMshUIUBr6VJXYkfyn3g8m5nrPR-z4S7LE82b2BnClq80EaPKnq__6w_VxkR/s320/i3.jpg" /></a></div><div class="separator" style="clear: both; text-align: center;"><em><strong><span style="font-size: x-small;">Fig 3: Principle of tube inspection from the outside with a 10MHz 128-element flat circular array and a mirror.</span></strong></em></div><div class="separator" style="clear: both; text-align: center;"><br />
</div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgdIoKzw2rQJFOlFtJLrNEdKjRcmbaxAWoNxIPvhpCMlAQhYTV6kZQqGJd9Y1BSjbGoV0ef9F59lahjwXWgQksV23uWwMPFOHAzYc146XpXJvAy5XUdHmkZF7kMUAOpI4Wh3Ix04GcyHX2W/s1600/i4.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" ru="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgdIoKzw2rQJFOlFtJLrNEdKjRcmbaxAWoNxIPvhpCMlAQhYTV6kZQqGJd9Y1BSjbGoV0ef9F59lahjwXWgQksV23uWwMPFOHAzYc146XpXJvAy5XUdHmkZF7kMUAOpI4Wh3Ix04GcyHX2W/s320/i4.jpg" /></a></div><div class="separator" style="clear: both; text-align: center;"><strong><em><span style="font-size: x-small;">Fig 4: Principle of a tube inspection from the inside with a 10MHz 128-element flat circular array and a mirror.</span></em></strong> </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;"><strong><em>Matrix array probes</em></strong> </div><div style="text-align: justify;"></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">These probes have an active area divided in two dimensions in different elements. This division can, for example, be in the form of a checkerboard, or sectored rings. These probes allow the ultrasonic beam to be driven in 3D by combining electronic focusing and deflection. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;"><strong><em>Main characteristics</em></strong></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Beyond their geometry, Phased Array probes offer the same flexibility of use as single-element probes. They can be used in immersion or in contact, their active area can be flat or focused, and they can also take into account the strong constraints of the industrial environment, such as temperature, pressure, vibration and radiation.</div><div style="text-align: justify;"><br />
</div><div style="text-align: center;"><strong>Examples of applications</strong> </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;"><strong><em>Inspection of blade roots and rotor steeples </em></strong></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">This inspection, carried out using various miniaturized phased array probes, one of which is shown in figure 1.3, has enabled many previously untested areas to be inspected. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">The use of phased array technology has enabled the use of beam-deflecting wedges to be avoided, and thus inspections to be carried out from restricted spaces inaccessible with other techniques. In addition, the probes’ electroacoustic performances have enabled the depth of detection and the accuracy of sizing to be increased (3).</div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiib4nFPugBe-D3b9hY8ehzPE0_1pmiJr-YmKD6BYl9S6JElRGZvP16HqYBmyoZeJVbHbZtaWZxabKH9u-p2mGo3mkKLXQWxXAds7NN32RhtX7akGh4rGh7csaY-kNN-8fSirTu8_33FXbw/s1600/i5.jpg" imageanchor="1" style="cssfloat: left; margin-left: 1em; margin-right: 1em;"><img border="0" ru="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiib4nFPugBe-D3b9hY8ehzPE0_1pmiJr-YmKD6BYl9S6JElRGZvP16HqYBmyoZeJVbHbZtaWZxabKH9u-p2mGo3mkKLXQWxXAds7NN32RhtX7akGh4rGh7csaY-kNN-8fSirTu8_33FXbw/s320/i5.jpg" /></a></div><div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none; text-align: center;"><strong><em><span style="font-size: x-small;">Fig 1: Examples of the use of phased array technology</span></em></strong></div><div style="text-align: center;"><strong><em><span style="font-size: x-small;"></span></em></strong></div><div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none; text-align: center;"><strong><em><span style="font-size: x-small;">1. Inspection of plate using a 10MHz 128-channel linear array transducer implementing electronic scanning and focusing </span></em></strong></div><div style="text-align: center;"><strong><em><span style="font-size: x-small;">2. Tube inspection from the inside using a 10MHz 80-channel focused circular array implementing electronic scanning and focusing </span></em></strong></div><div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none; text-align: center;"><strong><em><span style="font-size: x-small;">3. Inspection of blade roots using 10MHz 32-channel linear array contact transducers implementing electronic focusing and deflection. </span></em></strong></div><div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none; text-align: center;"><strong><em><span style="font-size: x-small;">4. Inspection of heavy forgings using a 5MHz 16- channel annular array implementing electronic focusing. </span></em></strong></div><div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none; text-align: center;"><strong><em><span style="font-size: x-small;">5. Inspection of welds with a 5MHz 32-channel linear array implementing electronic focusing and deflection. </span></em></strong></div><div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none; text-align: center;"><strong><em><span style="font-size: x-small;">6. In-line tube inspection from the outside with a 10MHz 256-channel circular array combining electronic scanning, focusing and deflection.</span></em></strong></div><div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none; text-align: justify;"><br />
</div><div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none; text-align: justify;"><strong><em>Inspection of tubes</em></strong> </div><div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none; text-align: justify;"></div><div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none; text-align: justify;"><br />
</div><div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none; text-align: justify;">Several phased array techniques can be used for inspecting tubes. In-line testing of tubes is generally done from the outside with encircling probes, as illustrated in figure 1.4. </div><div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none; text-align: justify;"><br />
</div><div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none; text-align: justify;">Inspection of heat exchanger tubes is generally done from the inside for reasons of accessibility. The generator tubes of the Superphœnix nuclear power plant were inspected from the inside using the phased array circular probes illustrated in figures 1.2 and 8. Here, phased array technology enabled the required testing speed to be achieved. In addition, the active area, made up of 80 elements, was focused by shaping to obtain the required beam characteristics (4). </div><div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none; text-align: justify;"><br />
</div><div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none; text-align: justify;">This inspection can also be carried out from the inside and from the outside by using a flat circular array associated with a mirror, as illustrated in figures 3 and 4.</div><div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none; text-align: justify;"><br />
</div><div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none; text-align: justify;"><em><strong>Inspection of titanium billets </strong></em></div><div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none; text-align: justify;"></div><div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none; text-align: justify;"><br />
</div><div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none; text-align: justify;">Titanium billets are traditionally inspected with sets of single-element probes, where each probe is dedicated to the inspection of a specific zone (depth range), for a specific diameter of billet. Although efficient in detecting defects, this solution has the major disadvantage of requiring many probes, and several shots to inspect a single billet.</div><div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none; text-align: justify;"><br />
</div><div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none; text-align: justify;">An alternative consists in using a matrix array. The cutting of the elements, such as shown in figure 5, and the electronic focusing and deflection enable the probes to be adapted to different diameters of billets and to different working depths.</div><div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none; text-align: justify;"><br />
</div><div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none; text-align: justify;">It is also possible to use the time reversal mirror technique (5), which has enabled flat-bottomed holes of a diameter of 0.4mm to be detected at a depth of 140mm, with a signal / noise ratio superior by at least 6dB to that obtained using any other technique </div><div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none; text-align: justify;"><br />
</div><div class="separator" style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none; clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhPeFDk0y6d6JH7M2c8-eyzfJwRPNjotOr4lr4EvHVMcavqIoxwX8Dk5ZT6cSAjs8taguYxiGtoeOSx85Thay7hAuwToIGugu8zhUnIUabJy-V6ebY6lIE9du_bug5hjYx3HuHMrwm8BowM/s1600/i6.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><strong><em><span style="font-size: x-small;"><img border="0" ru="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhPeFDk0y6d6JH7M2c8-eyzfJwRPNjotOr4lr4EvHVMcavqIoxwX8Dk5ZT6cSAjs8taguYxiGtoeOSx85Thay7hAuwToIGugu8zhUnIUabJy-V6ebY6lIE9du_bug5hjYx3HuHMrwm8BowM/s320/i6.jpg" /></span></em></strong></a></div><div class="separator" style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none; clear: both; text-align: center;"><strong><em><span style="font-size: x-small;">Fig 5: FERMAT matrix probe for inspecting titanium billets using the time reversal mirror technique (M.Fink ESPCI).</span></em></strong></div><div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none; text-align: justify;"><br />
</div><div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none; text-align: center;"><strong>Conclusión</strong></div><div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none; text-align: justify;"><br />
</div><div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none; text-align: justify;">The advantages of using Phased Array technology are the technical and economic benefits gained: </div><div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none; text-align: justify;"><br />
</div><ul><li><div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none; text-align: justify;">Traditional mechanical scanning is replaced by the much faster electronic scanning.</div></li>
<li><div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none; text-align: justify;">Electronic focusing allows the use of a single probe for working at different depths.</div></li>
<li><div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none; text-align: justify;">Electronic deflection allows the angles of incidence to be varied with only one probe.</div></li>
</ul><div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none; text-align: justify;">Costs are thus significantly reduced because of the inspection and adjustment time saved.</div><div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none; text-align: justify;"><br />
</div><div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none; text-align: justify;">In addition, phased array technology has made some applications possible that could not be resolved by traditional solutions, for example, when beam deflection is necessary without enough space to use a wedge (rotor steeple and blade root inspection) or when scanning is necessary without enough space for the corresponding mechanics (inspection of bent small-diameter tubes from the inside).</div><div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none; text-align: justify;"><br />
</div><div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none; text-align: justify;"><strong>Fuente:</strong> <a href="http://www.ndt.net/article/v07n05/poguet/poguet.htm">http://www.ndt.net/article/v07n05/poguet/poguet.htm</a></div><div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none; text-align: justify;"><strong>Ver blogger original</strong>: <a href="http://nubia-anc.blogspot.com/">http://nubia-anc.blogspot.com/</a></div><div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none; text-align: justify;"><strong>Materia: CRF</strong><br />
<div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none;"><img height="96" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiib4nFPugBe-D3b9hY8ehzPE0_1pmiJr-YmKD6BYl9S6JElRGZvP16HqYBmyoZeJVbHbZtaWZxabKH9u-p2mGo3mkKLXQWxXAds7NN32RhtX7akGh4rGh7csaY-kNN-8fSirTu8_33FXbw/s320/i5.jpg" style="filter: alpha(opacity=30); left: 68px; mozopacity: 0.3; opacity: 0.3; position: absolute; top: 3650px; visibility: hidden;" width="75" /></div></div>Nubia A. Navarro C.http://www.blogger.com/profile/16124874914747829398noreply@blogger.com0tag:blogger.com,1999:blog-5677235594720330703.post-61433974144262501412010-06-27T10:02:00.000-07:002010-06-27T10:02:04.673-07:00AEW&C - Phased Array Technology. Part 2<div style="text-align: justify;"><br />
</div><div style="text-align: justify;"><em><strong>Active phased array antenna technology promises significant improvements in AEW&C platform performance. While the technology base has yet to mature, the first designs using this technology are beginning to appear.</strong></em> </div><div style="text-align: justify;"></div><div style="text-align: justify;"><br />
</div><div style="text-align: center;"><strong><span style="font-size: large;">AEW&C using Active Phased Arrays</span></strong> </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">While the application of active arrays to AEW&C systems has been under discussion for many years, only two designs have been built to date and the technology has yet to reach full scale operational deployment. Applying the active array to an AEW&C platform introduces some interesting problems with antenna placement. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Conventional AEW&C systems have traditionally employed a rotodome, the characteristic saucer shaped radome which covers a conventional antenna, the rotodome rotating in order to scan 360 degrees about the platform. The placement of the rotodome on pylons, elevated well above the aircraft's fuselage, ensured that the antenna had an unobstructed field of view about the aircraft. This was achieved at considerable cost in weight, as the fuselage required strengthening to carry the structure, which itself wasn't featherweight. In typical designs, the rotodome is designed with an aerodynamic profile which produces, under cruise conditions, lift equal to the weight of the rotodome assembly, thus alleviating structural loading in cruise, but not necessarily in other configurations, unless the rotodome is built to tilt and thus change the AoA of its aerodynamic section. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">The rotodome arrangement is readily applicable to active array systems, as a four or three sided array may be fixed in the same position as the rotodome, providing 360 degree coverage and good clearance from the aircraft's structure. Lockheed have proposed a three sided array in this configuration, fitted to either a new airframe or the existing S-3 Viking airframe, to meet USN E-2C replacement requirements. The three or four sided array arrangement may be applied to any airframe able to accommodate a rotodome, and may well become the standard in years to come. Its only significant failing is that it retains much of the cost and weight penalties of the rotating rotodome. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Another configuration derived from this idea is that of the Swedish Ericsson Erieye, which uses a two sided array in a beam shaped structure, carried above the fuselage of a twin engined commuter airframe. The two sided array used in this arrangement is almost as long as the APY-2 antenna of the AWACS, potentially providing similar angular resolution performance at range, on a very small airframe. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">This arrangement however suffers from an obvious and significant operational limitation, as it cannot provide 360 degree coverage, using conventional active phased array technology. With each array scanning a 120 degree sector, the two sided array has a 60 degree blind sector over the nose and the tail of the aircraft, and degraded antenna performance beyond 45 degrees off the beam of the aircraft. With Sweden's compact geography this would probably not be an issue, as multiple platforms would cover a single area, and operating in pairs, the aircraft could patrol in two racetrack orbits set 90 degrees apart to provide overlapping coverage. The success of this scheme then devolves down to the capability of the computer datalink networking which links the platforms to each other or the ground air defence centre, to ensure that a comprehensive picture of the air situation exists at whatever is the central command post. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">In a heavy ECM environment, where platform to platform or platform to ground datalink function is interfered with, the two sided array has thus a major limitation. Producing a three or four sided array with similar array length results in a structure with a size comparable to an E-3 AWACS radome, which in turn requires at least a 737 sized aircraft to carry it, thereby largely defeating the apparent cost advantage of the linear array concept. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">A possible resolution would be the use of a supergain array, where the ultimate size of the blind sector would be determined by the array's module parameters and array length. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Another alternative which exists is the use of a rhombic four sided array geometry, with a 60-120-60-120 degree arrangement of arrays. While the rhombic arrangement will provide full 360 degree coverage, its effective antenna length is halved in the nose and tail sectors. The result is a compromise between the bulky but excellent four or three sided array, and the compact but partially blind two sided array. No publicly discussed proposals to date have involved the rhombic arrangement. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">An idea which has created some excitement in the engineering community is the concept of conformal active arrays or "smart skins", where active arrays are embedded in the skin of the aircraft, thus avoiding the structural, aerodynamic and weight penalties of an external radome. However, close examination of most existing airframe designs suggests they may not always accommodate this concept without some other penalties, such as coverage limitations like those suffered by the two sided array concept. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">The Israeli Phalcon system, which uses a B-707 airframe, was reported initially to have been the first implementation of this scheme. The aircraft's public debut has however shown this not to be true, as the aircraft uses fuselage mounted boxes for its main sidelooking arrays, and a nose mounted radome for a smaller forward looking array. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">The fuselage mounted linear arrays provide for excellent coverage over the beam aspect 120 degree sectors, but the nose and (reported optional) tail mounted arrays which "plug" the holes in beam array coverage are much shorter due fuselage diameter and thus would suffer a major loss in resolution performance fore and aft. Again the use of supergain array techniques could alleviate this problem. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">As with two sided and rhombic array configurations, the Phalcon arrangement may or may not be suitable for a given operational environment. Where the threat axis is defined unambiguously and the aircraft's patrol racetrack can be aligned appropriately, the coverage limitations may not be of significant importance. Where the threat can approach from multiple axes concurrently, full 360 degree coverage is almost mandatory. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Westinghouse's MESA system which is currently in development, uses a podded arrangement of sidelooking linear arrays carried by a C-130, with some reports suggesting that supplementary nose and tail arrays could be fitted to plug nose and tail coverage. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Other alternatives do exist. An arrangement publicised by Boeing for the now defunct USN E-X program involved the use of an airframe with a trapezoidal (diamond shaped) wing, with arrays embedded in the wing surfaces to provide 360 degree coverage. The S-3 sized aircraft had been proposed to replace the E-2C. Recent budget cuts have put its future very much in doubt. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">The dilemma faced by designers is simple: active arrays provide the potential for a small airframe to have E-3 AWACS class antenna performance, however antenna coverage requirements will force the use of a either a mast mounted radome or a new airframe geometry, both negating the potential cost advantage offered by the antenna technology. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Other alternatives may yet exist, but investigating their suitability will require some effort by airframe manufacturers. Most modern airliner airframes have a wing sweep of about 60 degrees, which suggests that the leading edges of the wings have the almost ideal geometry to accommodate conformal arrays. A six to eight metre conformal array embedded in the leading edge, inboard, would automatically provide two sides of the three sided array configuration. The problem is that this would preclude the use of leading edge lift devices over at least 30% of the span, and also preclude the use of wing mounted engines, which would obstruct the array's field of view. The unresolved issue is the third side of the array, which could only be implemented by placing an array on the tail of the aircraft. A six to eight metre array length will require, by default, a beam structure of similar size. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Closer examination of available airframes suggests that those with aft mounted engines (B-727, MD-80) would be geometrically most suited to leading edge array placement, but the positioning of the powerplants would cause difficulties in positioning the tail array. The optimal geometry would see engine pods mounted above the wings (cf VFW-614), and the tail array beam structure fitted to the end of the fuselage, or at the top of the vertical stabiliser. The scale of change would again force a new airframe design, or substantial rework of an existing design. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">The application of supergain array techniques could of course alleviate many of these difficulties, and it remains to be seen how soon this technology becomes adapted to an AEW&C application. Clearly as the technology of active phased arrays matures, designers will settle upon the most suitable configurations, but as is often the case, the simple and orthodox solutions may ultimately prevail simply because they were a good idea in the first place. The pylon mounted radome may be with us for some time to come. </div><div style="text-align: justify;"><br />
</div><div style="text-align: center;"><strong><span style="font-size: large;">The Australian Perspective</span></strong> </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Australia has some unique problems in acquiring its future AEW&C capability. These revolve primarily about the operational requirements associated with the range of missions to be performed, further complicated by the geography of our landmass. Projected RAAF AEW&C operations can be basically divided into the support of air defence (DCA or Defensive Counter-Air), and the support of maritime operations and OCA (Offensive Counter Air). Existing doctrine is focussed on DCA (AAP1000-Ch.5). </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Local air defence of point targets can at a minimum, be performed by a smaller aircraft with lesser radar range, the requirement being centred on the ability to quickly get an aircraft aloft to a station within 200 NM of the runway in use, and to provide 2-4 hours of time on station. Given the concentration of potential targets in the North into specific areas and potential threat axes, 360 degree coverage may not be a mandatory requirement. Supported by long range threat warning from Jindalee, this mission can be performed readily by a smaller twin engined aircraft. The proximity to a land base means that the requirements imposed insofar as Command/Control/Communications go are modest, because land based facilities may be used to support the mission. Wider coverage of the large expanses of the North would however preclude this approach. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Providing AEW&C support for DCA in the air-sea gap, maritime operations and OCA becomes a more demanding affair, as the area of operations may be several hundred nautical miles from the operating base, over the ocean, out of the reach of land based UHF comms and exposed to enemy air attack from many axes. These conditions impose the requirement for considerable range and endurance, to ensure that the AEW&C aircraft can remain on station for a substantial time, and also demand comprehensive C3 capability and 360 degree radar, IFF and ESM coverage. Good radar range is also to an advantage, as is transit speed to station and inflight refuelling capability. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">All AEW&C systems in use today reflect these operational requirements. The E-3 has superb radius, endurance, radar coverage and a comprehensive C3 suite, which allows for wholly autonomous operation as an airborne command post. The former Soviet Mainstay was designed to a similar requirement. The E-2C, optimised for local air defence in the maritime carrier environment, has limited range, endurance, C3 capability and radar performance, although it does provide the necessary 360 degree coverage. The SAAB-2000/Erieye has endurance and range in the class of the E-2C, limited C3 capability, and limited coverage, reflecting the local air defence requirements of the congested airspace of the Baltic, and predictable threat axes. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">In the Australian context, the question is whether we can effectively capitalise upon the emerging technology of active arrays. The RAAF in defining its AEW&C requirement will ultimately have to decide whether to opt for a twin engined system limited to localised DCA operations, closely coupled to ground C3 facilities and hence depart from established doctrine, or whether to opt for an extended AEW&C umbrella satisfying existing DCA doctrine and encompassing RAAF OCA and RAN operations, and hence select a longer ranging four engined aircraft capable of performing as a self contained command post. Existing RAAF DCA doctrine (AAP1000-5.41,5.42) stresses the latter approach. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">The central question in this matter is whether the RAAF will define its requirement in the context of recent doctrine, opting for a longer ranging platform, or whether it will yield to the inevitable financial pressure from the government to select a smaller and less capable aircraft. The selection of off-the-shelf candidates which meet stated doctrine and obvious requirements is both limited and split between older conventional technology and newer array technology. The alternative would then be a custom integration exercise, combining active array radar with a platform and array geometry not necessarily used at this time by the radar vendor. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">What is significant in this context is that judicious choice of airframe and array geometry could minimise integration costs, while providing scope for domestic integration work which would in turn bolster our domestic defence industry, and ease longer term support costs for the design once in service. It is central in this debate that the government recognise that short term acquisition cost advantages may not translate into a cost or operational advantage over the whole life cycle of the AEW&C system, and hence that the government does not pressure the RAAF in the direction of short term expediency. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Active array technology promises major gains in the capability of both medium sized and smaller AEW&C systems, but to capitalise fully on these gains will require further integration effort. Australia has in many senses a unique operational environment and it would not be wise to bend requirements to fit established and very much development systems. We can hope the government will recognise this when it eventually proceeds with the AEW&C acquisition. </div><div style="text-align: justify;"><br />
</div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjoLsbmu84VUgwfrswqW5oyUHN6QY8cZFmX0iFhXxEYLsziPgRFnhGlFd-amLIOXC9bEfGR07_9weRFQDmaup2ipu7TKzC3zma8l3etknivSALyucF13i2N8TTWO2nwkB3DT2s375hhu5wE/s1600/21.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" ru="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjoLsbmu84VUgwfrswqW5oyUHN6QY8cZFmX0iFhXxEYLsziPgRFnhGlFd-amLIOXC9bEfGR07_9weRFQDmaup2ipu7TKzC3zma8l3etknivSALyucF13i2N8TTWO2nwkB3DT2s375hhu5wE/s320/21.jpg" /></a></div><div class="separator" style="clear: both; text-align: center;"><br />
</div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgBPmFga4ZYgb4PJu6hRSTuWmbNWRZtgBADc5IN86oREQ62WdCjlFh2LFh-sY6p_QJXxm5_qEDaeYY2NmgXolK-eHhvmr8DvPBVtRGWKOmRsZULK0shhZEHWk4-jtrP5V76USdeKr14Pu7G/s1600/22.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" ru="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgBPmFga4ZYgb4PJu6hRSTuWmbNWRZtgBADc5IN86oREQ62WdCjlFh2LFh-sY6p_QJXxm5_qEDaeYY2NmgXolK-eHhvmr8DvPBVtRGWKOmRsZULK0shhZEHWk4-jtrP5V76USdeKr14Pu7G/s320/22.jpg" /></a></div><div class="separator" style="clear: both; text-align: justify;"><em>The Boeing E-3 AWACS was the first AEW&C platform to use a limited amount of phased array technology in its APY-1/2 surveillance radar. The APY-1/2 utilises a slotted planar array which scans azimuth mechanically and height electronically. With the closure of 707 airframe production, Boeing will integrate the system with a newer widebody airframe.</em></div><div class="separator" style="clear: both; text-align: justify;"><br />
</div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgju40_-VZF1SGTO0H9P1yFBqirLleW-FI36TEE1nK5z6JzMYw0xuayEPjQgaZw6kEd5bwTprzk-JH_LiHdXwGlcuOBYS-k7VB-YYXc9jTgeOl7WV30iuEc86RznQMeaz9Km9ZqQs-fhHLF/s1600/23.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" ru="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgju40_-VZF1SGTO0H9P1yFBqirLleW-FI36TEE1nK5z6JzMYw0xuayEPjQgaZw6kEd5bwTprzk-JH_LiHdXwGlcuOBYS-k7VB-YYXc9jTgeOl7WV30iuEc86RznQMeaz9Km9ZqQs-fhHLF/s320/23.jpg" /></a></div><div class="separator" style="clear: both; text-align: justify;"><em>The Ericsson Erieye system uses an active phased array radar mounted in a two sided array geometry. The whole array is contained in a large beam shaped structure carried above the fuselage of a commuter twin airframe. The limitation of the two sided array is that it can only cover two 120 degree sectors abeam of the aircraft, leaving 60 degree blind sectors over the nose and tail of the aircraft, and reduced antenna performance from 45 degrees off the beam aspect. Another limitation stems from the use of an airframe too small to accommodate a comprehensive self contained command, control and communications system, and other sensors such as a capable ESM and track association system. </em></div><div style="text-align: justify;"><em></em></div><em><div style="text-align: justify;"><br />
</div></em><div style="text-align: justify;"><em>Pic.3 (Phalcon - not enclosed) </em></div><em><div style="text-align: justify;"><br />
</div></em><div style="text-align: justify;"><em>The Israeli Phalcon is the first full scale application of phased array technology, using arrays along the fuselage and under the nose and tail. While providing full 360 degree coverage, the smaller size of the nose and tail arrays will limit angular resolution in the nose and tail sectors, thus degrading system performance in these areas. While cheaper than external pylon mounted radomes in terms of structural modifications, conformal arrays require suitable airframe geometry if they are to be used to full advantage.</em> </div><br />
<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh7RCSVMje2m1cpKzXPJZUOAJO9qV39gSGclVLMiAbBcqH6UC68lO_kHiXrFRzkJd43X87Ay9mru2kisjSJxoxjcLQUaNuMuqMU3eHUgFVC0e7CjPzK3WmxGcjhyphenhyphenWgtO4jsLLzstdXijtIp/s1600/24.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" ru="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh7RCSVMje2m1cpKzXPJZUOAJO9qV39gSGclVLMiAbBcqH6UC68lO_kHiXrFRzkJd43X87Ay9mru2kisjSJxoxjcLQUaNuMuqMU3eHUgFVC0e7CjPzK3WmxGcjhyphenhyphenWgtO4jsLLzstdXijtIp/s320/24.jpg" /></a></div><div class="separator" style="clear: both; text-align: justify;"><em>This AMSS Lockheed proposal for an E-2C replacement depicts a three sided array geometry. Three sided and four sided arrays offer 360 degree coverage without significant degradation in angular resolution against azimuth, but incur the cost, weight and drag penalties of the radome structures. At the time of writing no design using this geometry has been flown.</em></div><div class="separator" style="clear: both; text-align: justify;"><br />
</div><div class="separator" style="clear: both; text-align: justify;"><strong>Fuente:</strong> <a href="http://www.ausairpower.net/aew-aesa.html">http://www.ausairpower.net/aew-aesa.html</a></div><div class="separator" style="clear: both; text-align: justify;"><strong>Ver blogger original:</strong> <a href="http://nubia-anc.blogspot.com/">http://nubia-anc.blogspot.com/</a></div><div class="separator" style="clear: both; text-align: justify;"><strong>Materia: CRF</strong></div>Nubia A. Navarro C.http://www.blogger.com/profile/16124874914747829398noreply@blogger.com0tag:blogger.com,1999:blog-5677235594720330703.post-17750734044346822652010-06-27T09:52:00.000-07:002010-06-27T09:53:46.267-07:00AEW&C - Phased Array Technology. Part 1<div style="text-align: center;"><br />
</div><div style="text-align: center;"><strong><em>Australian Aviation, 1994 </em></strong></div><div style="text-align: center;"><strong><em></em></strong></div><div style="text-align: center;"><strong><em>by Carlo Kopp</em></strong></div><div style="text-align: center;"><strong><em>© 1996, 2005 Carlo Kopp</em></strong> </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;"><strong><em>The technology of Airborne Early Warning (AEW&C) systems is at a generational junction point at this time. We are now witnessing the next step in the lengthy evolution of this key technology, that being the transition from mechanically scanned antenna technology to electronically scanned phased array technology.</em></strong> </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Phased array antenna technology has been in use for some decades, but most applications have been confined to ground based systems, due significant weight and size penalties associated with older families of electronic devices. The ongoing march of miniaturisation combined with significant improvements in microwave power transistor device technology has now allowed its wider use in airborne applications. </div><div style="text-align: justify;"><br />
</div><div style="text-align: center;"><strong><span style="font-size: large;">Conventional Antenna Systems</span></strong> </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">The purpose of a radar antenna is to focus a beam of electromagnetic energy into a desired shape and direction, and due some of the nicer properties of electromagnetism, the shape of the transmitted beam is identical to the shape of the antenna's sensitivity pattern when receiving. In an AEW&C application, and typically most airborne surveillance applications, the shape of the beam is designed to maximise the chances of detecting a distant and small target. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">But this is not the only requirement which exists, as an AEW&C platform must also have the ability to track targets, find their altitude and resist the effects of jamming by inbound hostiles. These are often contradictory requirements in terms of what the antenna must do, as the search and detect function typically requires a broader beam to cover as large a possible volume of airspace in a single sweep, whereas the tracking function requires as tight a beam as is possible to provide the ability to resolve multiple closely spaced targets, and determine their position as accurately as possible. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">A key issue in the design of such antennas is sidelobe performance, sidelobes being spurious and unwanted beams produced by the antenna in directions other than that of the principal beam, the mainlobe. Sidelobes have typically unhealthy effects on a radar system, which by its nature cannot tell whether the energy which it is receiving originated in the mainlobe or the sidelobe. In airborne lookdown radars, which are typically MTIs (Moving Target Indicators) in lower band systems, or pulse Doppler in the microwave bands, sidelobes can inject energy reflected off the airframe and underlying terrain with Doppler shifts which are very different from the Doppler being used as a reference by the electronics which sift through the mainlobe return searching for targets. This can degrade performance if appropriate measures are not taken. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">There is another insidious side effect of sidelobes, and that is that they render the radar vulnerable to hostile jamming and anti radiation missiles (ARM). False target generator jammers will typically exploit sidelobing, injecting false target returns into the system via a sidelobe, thus creating the illusion of targets in the mainlobe, where none exist. ARMs will home in on the stray sidelobe emissions, which enable them to track the radar even if it is pointing elsewhere. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">As is clearly evident, designing an antenna system for an AEW&C platform is not a trivial task, even for the experts, and many differing solutions have been devised over the last five decades. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">The oldest and least effective approach was to produce one of a variety of rotating concave (dish shape) sections, typically based on paraboloid shapes, producing a narrow beam by using a horizontally wider section (ie horizontal orange peel shape), height finding being implemented by switching the beam via several mechanically offset antenna feeds. This meant that one of several beams was active at any time, and each of these beams covered a different range of altitudes. While this is a cumbersome arrangement, it is easy to build, and many systems in the fifties and early sixties used this arrangement. Its principal weakness is poor sidelobe performance, and slow response when height finding. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">The venerable Lockheed E/RC-121 and WV-2 Warning Star (Connie) and Avro Shackleton AEW&C.2 used this class of antenna, albeit without height finding capability. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">The next step in the evolution of AEW&C antennas was the use of fixed arrays. The idea of an antenna array is very simple and elegant. Instead of designing a single complex antenna shape, the array uses a group of much simpler antenna shapes, and combines their individual signals together. In the fashion, all the mainlobes are added together, and if this is done correctly, a much tighter single mainlobe is produced. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">One of the key constraints was that of beamwidth, and the basic rule which applies is that for a given radar wavelength (frequency), the wider the antenna or antenna array, the tighter (narrower) the beam. Typically, the tighter the beam mainlobe, the weaker the sidelobes. This of course introduces a problem in airborne applications, as the bigger the antenna, the bigger the airframe required to carry it, and hence the cost will increase dramatically. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">The use of arrays allowed the design of much more compact antennas, and the sixties E-2C AEW&C and seventies E-3 AWACS both capitalised upon this technology to maximise the performance of their antenna designs. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">The E-2C uses a family of radars, the APS-125/138/139/145, all of which employ derivatives of the APA-171 antenna assembly in a dorsal radome (saucer shaped). The antenna arrangement hidden under the plastic is a horizontal array of UHF band Yagi antennas. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">The bigger E-3A/B/C/D/F uses the larger and more sophisticated APY-1 or 2 pulse Doppler radar, which uses an E/F band microwave slotted planar array. The slotted planar array is a microwave antenna, which uses hundreds or thousands of tiny slots, each slot acting as a very simple antenna element. A complex network of waveguides and delay elements hidden behind the antenna array times the arrival of the microwave signals in such a fashion, that the antenna produces a very tight mainlobe beam, and very small sidelobes. As with a conventional radar, the transmitter uses a large Travelling Wave Tube (TWT) microwave amplifier (usually dual redundant in the E-3) which pumps the very powerful microwave signal into the antenna. In the opposite direction, the slots/waveguides/delay elements feed into a redundant receiver which then in turn feeds a conventional pulse Doppler signal processing chain. The antenna scans in azimuth by the whole antenna assembly being rotated upon its pedestal at 6 RPM, through 360 degrees. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Both the E-2C and the E-3 integrate a primary and secondary radar capability, the secondary/IFF antennas are mounted back to back with the primary radar antenna. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">This family of microwave antennas was the first to see a limited application of of the phased array principles to be discussed, and this is typically used for the height finding function. </div><div style="text-align: justify;"><br />
</div><div style="text-align: center;"><strong><span style="font-size: large;">Phased Arrays - An Introduction</span></strong> </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">The phased array is extension of the idea of the planar array. In the planar array, the beam is fixed in direction and shape, because the timing of the microwaves fed into the array is fixed. However, if the timing can be varied, then both the shape of the beam and its direction can be changed. If this is done electronically, the shape and direction of the beam can be changed in a very small fraction of a second. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Needless to say, this can be as daunting a task as it appears to be, because several hundred or thousand array elements must be retimed simultaneously. The key elements in building such an array are the programmable phase shifter (or more colloquially, "shifter"), a device which can change the phase (ie time delay or timing) of the microwaves passing through it under electronic control, and the ubiquitous digital computer. Using the computer to control the shifters, the whole array becomes in effect an antenna with software programmable beam shape and direction. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Until the late eighties, building such a system involved a substantial volume of hardware, which meant that fully electronically steerable phased arrays were mainly used in surface based applications, such as the massive BMEWS ballistic missile warning radars and the somewhat smaller US Navy SPY-1 Aegis air defence radar, carried on the Ticonderoga class cruisers and more recently, the Arleigh Burke destroyer. The only known airborne applications were the large Flash Dance radar fitted to the gargantuan Soviet Foxhound air defence interceptor, and the attack radar in the Rockwell B-1B Lancer. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Airborne applications suffered mostly from the penalty of weight, as the first generation of phased array technology used a substantially conventional radar architecture. While the antenna changed, all else remained as was, but additional computer hardware was added to control the antenna shifters. This translated into a heavier antenna, an extra computer, and extra power loading on the electrical system resulting in bigger accessory generators. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">The performance benefits of the phased array however justified the extra cost. The phased array could in a single antenna do the jobs of several purpose built antennas, almost simultaneously. Wide beams could be used for searching, narrow beams for tracking, flat fan shaped beams for height finding and narrow pencil beams for terrain following (B-1B). In a hostile jamming environment the benefits were even greater, as phased arrays allow the system to place a "null", an area of zero receiver sensitivity, over a jammer and thus in effect block it from entering the receiver chain. Another benefit, although minor in non-surveillance applications, is that there is no longer the need to mechanically point the antenna in the direction of the target. Typically a multiple sided antenna arrangement could provide 360 coverage, with fixed antennas covering all directions at once. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Less obvious benefits also flowed from this technology. One was the ability to rapidly scan a small sector of sky to increase the likelihood of detecting a small and fleeting target, unlike a slowly rotating antenna which can only scan a particular sector once per rotation, typically seconds apart. A small target like a low flying cruise missile may be almost impossible to track under such conditions. The phased array's ability to almost instantaneously change beam direction and shape in fact adds a whole new dimension to tracking, as multiple targets may be tracked by multiple beams, all of which are interleaved in time with a periodically scanning search beam. As an instance, a search beam may sweep 360 degrees periodically, while tracking beams can follow individual targets regardless of where the search beam is looking at, at the time. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Significant as these gains may have been, the first generation of this technology was simply too physically cumbersome to penetrate into the AEW&C environment. The E-3 uses a limited phased array capability, in that the APY-1/2 can height find through vertical beam steering, this was implementable at modest cost as the antenna slots could be controlled in horizontal "stripes" to achieve this functionality. A shifter is thus only required for each stripe, thus cutting their number down to something modest, rather than thousands. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Phased arrays do have their limitations, as all designs have. The principal limitation is the range of angles through which the beam can be steered. In practice, the limit is about 45 to 60 degrees off the vertical to the plane of the antenna, steering the beam to shallower angles degrades antenna performance significantly. Two effects are at play here. The first of these is that the effective length (width) of the antenna is reduced with increasing beam deflection angle (for technical readers the effective length L' becomes L'=L.cos(A), where L is the physical array length and A the angle off the antenna axis, at the array boresight L'=L, falling to 0.5L at 60 degrees and zero at 90 degrees), reducing array length in turn diminishes its ability to resolve targets at a distance, while also reducing antenna gain, a measure of its efficiency. The second effect is less apparent, but derives from the radiation pattern of the constituent elements, the slots, which radiate less with increasing angle off the vertical, thus reducing the power transmitted and the sensitivity. In effect, at extreme angles the mainlobe is both substantially weakened and defocussed (technical readers are directed to Eli Brookner's item in Scientific American Feb 1985, pp 76 for a more detailed discussion). So substantial is this reduction, that a typical situation would see antenna gain, and hence power radiated and sensitivity, cut down to 25% at 60 degrees off the vertical. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">The application of phased arrays to AEW&C technology had to wait for another technological development, that being the active phased array. In an active phased array, each array element or group of elements has its own miniature microwave transmitter, dispensing with the single large transmitter tube of the older passive array technology. In an active phased array, each element is comprised of a module which contains the antenna slot, phase shifter, transmitter, and often also a receiver. In a conventional passive array, a single transmitter of several hundred kiloWatts of power feeds several thousand elements, each of which emits only tens of Watts of power each. A modern microwave transistor amplifier can, however, also produce tens of Watts, and in an active phased array design, several thousand modules each producing tens of Watts of power add up to an equally powerful mainlobe of hundreds of kiloWatts. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">While the final effect is identical, the active array is far more reliable, as the failure of any array element merely degrades antenna performance by a fraction of a percent. This is graceful degradation, as the catastrophic transmitter tube failures which plague conventional radar simply cannot occur. A side benefit is the weight saving incurred by dispensing with the bulky high power tube, its associated cooling system and its large high voltage power supply. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Another powerful feature which may be exploited only in active arrays, is the ability to control the gain of the individual transmit/receive/shifter modules. If this can be done, the range of angles through which the beam can be swept is increased substantially, and thus many of the array geometry constraints which plague the conventional phased array may be circumvented. Such arrays are termed supergain arrays. From published literature it is unclear whether any existing or development designs use this technique, and the coverage limits indicated for some existing designs suggest that this is not the case as yet. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">In summary it is fair to say that the active phased array outclasses conventional radar designs in almost all respects, providing superior performance, tracking capability and reliability, albeit at some penalty in complexity and possibly cost. </div><div style="text-align: justify;"><br />
</div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh04p31a7NhghTuQfYpYjIaoKqTbkbviP-s3ozR_DYXBP1Q1MkNECtYwHOOxI41Y5ld8a482FDJYf2uo_jYAGzW2prDzUy1wPt7Oki5PIdgn8EUAvFYwokZAiWS-K51WAn2jhhRGTBHvBb6/s1600/16.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" ru="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh04p31a7NhghTuQfYpYjIaoKqTbkbviP-s3ozR_DYXBP1Q1MkNECtYwHOOxI41Y5ld8a482FDJYf2uo_jYAGzW2prDzUy1wPt7Oki5PIdgn8EUAvFYwokZAiWS-K51WAn2jhhRGTBHvBb6/s320/16.jpg" /></a></div><div class="separator" style="clear: both; text-align: justify;"><em>The venerable Hawkeye is the mainstay of US Navy AEW squadrons, as well as being used by Israel and Singapore. The APS-125/138/145 systems carried by subtypes of this aircraft are based on sixties UHF antenna technology, using the APA-171 radome which contains an array of Yagi antennas. Its strength is maturity and simplicity, and it delivers very good performance in its maritime environment (AEWA).</em> </div><div style="text-align: justify;"><br />
</div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgzzKDITqHYfq71S8iu-I9Jx3Z3TshmQwmX28G-orTObUX3BNo4Sqf75XJErDnOWZAy_rgpQLAdKgBidGsaeJDwpmWbm9uhgkODbrkQyColHedTzNj2kGfnUEteQK4hShqAVB-YDKeex_qM/s1600/17.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" ru="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgzzKDITqHYfq71S8iu-I9Jx3Z3TshmQwmX28G-orTObUX3BNo4Sqf75XJErDnOWZAy_rgpQLAdKgBidGsaeJDwpmWbm9uhgkODbrkQyColHedTzNj2kGfnUEteQK4hShqAVB-YDKeex_qM/s320/17.jpg" /></a></div><div class="separator" style="clear: both; text-align: justify;"><em>The AWACS is the flagship of US AEW technology, based on evolved versions of the 1970s APY-1 radar. The APY-1 and 2 radars are microwave E/F band systems, with mechanical rotodome scan in azimuth and phased array techniques in heightfinding. The system delivers superlative long range detection and tracking performance, but is penalised by size and weight, which impose the need for a large airframe (C-137/B-707 or widebody) and this reflects in high acquisition and support cost (AEWA).</em> </div><div class="separator" style="clear: both; text-align: justify;"> </div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEihmCphkplv4_92NNI5I5AGkS3jtsWFa6CGnA-XuJnjYxOGkhsuIebfPiRhvw10aF2XvtG1fLTGQUp_EH6QXfmVowIpGhdjELWxiqcq6WOpLrnh5MwMDVHj2-i7cfcC51t0m5zEqYZFpmA4/s1600/18.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" ru="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEihmCphkplv4_92NNI5I5AGkS3jtsWFa6CGnA-XuJnjYxOGkhsuIebfPiRhvw10aF2XvtG1fLTGQUp_EH6QXfmVowIpGhdjELWxiqcq6WOpLrnh5MwMDVHj2-i7cfcC51t0m5zEqYZFpmA4/s320/18.jpg" /></a></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEik3XedDfSQzWLPb4USR9izj37TH8fb8VRpG4HHgAh8-L-DQX7ugTaqbNbEEC8ahvjF3z_j5Kns5DLOTR1uU38Ncp5SOmgg3t9WqsxroTiVwzZqtXLs4q2qGJGqwlKxv2bRGthOqfC6cYU4/s1600/19.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" ru="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEik3XedDfSQzWLPb4USR9izj37TH8fb8VRpG4HHgAh8-L-DQX7ugTaqbNbEEC8ahvjF3z_j5Kns5DLOTR1uU38Ncp5SOmgg3t9WqsxroTiVwzZqtXLs4q2qGJGqwlKxv2bRGthOqfC6cYU4/s320/19.jpg" /></a></div><div class="separator" style="clear: both; text-align: justify;"><em>The Hawkeye's UHF radar has been integrated with both the Lockheed P-3 and C-130 airframes, providing a mid range system with substantially better range and endurance performance than the E-2C. These derivative systems exploit the additional airframe volume available and use larger and newer computer and display technology, in comparison with the cramped E-2C airframe.</em></div><div class="separator" style="clear: both; text-align: justify;"><br />
</div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgko2gdFOYtZFdQb4-Z-X5pj2w1Q8_iFFgJMKhHS-b0IZzHNuDuz5r81ws-QlEWZuf1E-7OX9tWM_KIPGTmU8IwLG2_hdmFbyNp3pupGbkn84Zir9f07n39ZaYmcA5z-drzVKOsH_rlRTwW/s1600/20.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" ru="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgko2gdFOYtZFdQb4-Z-X5pj2w1Q8_iFFgJMKhHS-b0IZzHNuDuz5r81ws-QlEWZuf1E-7OX9tWM_KIPGTmU8IwLG2_hdmFbyNp3pupGbkn84Zir9f07n39ZaYmcA5z-drzVKOsH_rlRTwW/s320/20.jpg" /></a></div><div class="separator" style="clear: both; text-align: justify;"><em>The best known phased array radar in use today is the US Navy's SPY-1 Aegis, a large passive array system fitted to Ticonderoga class cruisers. The large SPY-1 has four 3.65 x 3.65 m arrays, each with 4100 elements, and can concurrently track several hundred targets at a range of altitudes. Designed to counter saturation attacks by several hundred anti-ship cruise missiles, the radar relies heavily on its ability to flexibly allocate its system computing power to best advantage, and vividly illustrates the potential of modern phased array technology (LM Photo).</em></div><br />
<strong>Fuente:</strong> <a href="http://www.ausairpower.net/aew-aesa.html">http://www.ausairpower.net/aew-aesa.html</a><br />
<strong>Ver blogger original:</strong> <a href="http://nubia-anc.blogspot.com/">http://nubia-anc.blogspot.com/</a><br />
<strong>Materia: CRF</strong>Nubia A. Navarro C.http://www.blogger.com/profile/16124874914747829398noreply@blogger.com0tag:blogger.com,1999:blog-5677235594720330703.post-82159946116490498122010-06-27T09:31:00.000-07:002010-06-27T09:31:21.978-07:00SMART-S<div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Manufacturer: Hollandse Signaalapparaten BV, Niederlande, www.signaal.nl</div><div style="text-align: justify;"></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">SMART-S (Signaal Multibeam Acquisition Radar for Targeting) is an all-weather 3-D target indication and surveillance radar system intended for all types of naval vessels from fast patrol boats upwards. Its prime application is as the main sensor for data handling and weapon system control, and it has a very high performance in the presence of heavy clutter and electronic countermeasures. The equipment has been designed to cope with small high-speed anti-ship missiles with radar cross-sections down to 0.1 m2 and approach speeds of Mach 3+, which can be either sea skimmers or arriving from high angles of 70° or more.</div><div style="text-align: justify;"><br />
</div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjdMBAjaLNok2toZHXHFqW1XqoWIzpWytheQDhLf9xh6hYbuO-_0nS4quPhRbCf3LJhKXOsG7LbhqSPbQJ_8enSZrNy8A5ofHu5vyf5ekobxMlSpAoBwCSl3opgHvD1CwVeYvmwvSGWPv3N/s1600/15.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" ru="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjdMBAjaLNok2toZHXHFqW1XqoWIzpWytheQDhLf9xh6hYbuO-_0nS4quPhRbCf3LJhKXOsG7LbhqSPbQJ_8enSZrNy8A5ofHu5vyf5ekobxMlSpAoBwCSl3opgHvD1CwVeYvmwvSGWPv3N/s320/15.jpg" /></a></div><div class="separator" style="clear: both; text-align: center;"><strong><em><span style="font-size: x-small;">Figure 1: SMART-S antenna (Source: Jane's Information Group)</span></em></strong></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">The SMART system operates in F-Band (the traditional of this frequency band name was S-Band, the designator is SMART-S therefore), where it offers an optimum balance between range, clutter rejection and antenna dimensions. It provides automatic detection, track initiation and track maintenance of both air and surface threats, with gapless coverage over a complete hemisphere from the sea surface upwards. It incorporates anti-clutter and electronic counter-countermeasures features such as multiple reception beams with ultra-low sidelobes in elevation and azimuth, a clutter analysis sensor, broadband transmission, pulse repetition frequency and radio frequency agility per burst and a jamming analysis sensor. SMART is designed to track 160 air targets and 40 surface targets simultaneously.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">The system comprises an antenna and three main below-decks units. The hydraulically stabilised antenna consists of a single-element wideband transmitting array, and a multi-element stripline receiving array. The ultra-low sidelobe phased array allows the formation of multiple receive beams in elevation. To ensure high sensitivity, preprocessing of the received signals takes place in the antenna unit itself. The output of the 16 antennas is fed to a digital beam forming network in which the 12 independent elevation beams are produced, after which Doppler Fast Fourier Transform processing and automatic tracking is carried out. The transmitter is based on a high power, pulse-to-pulse coherent Traveling Wave Tube. Integral identification friend-or-foe can be provided.</div><br />
<strong>Specifications </strong><br />
<br />
Frequency: F-Band <br />
Peak power: 145 kilowatts <br />
Displayed range: 55 nautical miles <br />
Range resolution: 0.5 nautical miles <br />
Beamwidth: 2 degrees <br />
Antenna rotation: 2.22 seconds (27 rpm.) <br />
<br />
<strong>Fuente:</strong> <a href="http://www.radartutorial.eu/19.kartei/karte507.en.html">http://www.radartutorial.eu/19.kartei/karte507.en.html</a> <br />
<strong>Ver blogger original:</strong> <a href="http://nubia-anc.blogspot.com/">http://nubia-anc.blogspot.com/</a> <br />
<strong>Materia: CRF</strong>Nubia A. Navarro C.http://www.blogger.com/profile/16124874914747829398noreply@blogger.com0tag:blogger.com,1999:blog-5677235594720330703.post-92231394204127647742010-06-27T09:10:00.000-07:002010-06-27T09:13:15.002-07:00Phased array<div style="text-align: justify;"><br />
Un phased array ("agrupación de antenas controladas por fase") es un conjunto de antenas (array) en el cual las fases relativas de las señales con que se alimenta cada antena se varían intencionadamente con objeto de alterar el diagrama de radiación del conjunto. Lo normal es reforzar la radiación en una dirección concreta y suprimirla en direcciones indeseadas.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Esta tecnología fue desarrollada originalmente por el futuro Premio Nobel Luis Walter Álvarez durante la Segunda Guerra Mundial, para funcionar en radares de respuesta rápida destinados a aplicaciones de Ground-Controlled Approach (GCA), es decir, de ayuda al aterrizaje de aeronaves. Más tarde se adaptó para usos en radioastronomía, valiéndole el Premio Nobel de Física a Anthony Hewish y Martin Ryle, tras desarrollar phased arrays de gran tamaño en la Universidad de Cambridge. El diseño se usa por tanto en radar y es de uso habitual en antenas de radio interferométricas.</div><div style="text-align: justify;"><br />
</div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiwm1J_8B1TBlU-L-PiMMZG_0HGXFdJ6e4s9rsSdQ0xnTUZKtark0pZtiRC-8cA_M4F-6jZMDRqH6U_K1QhG19giHWBx8LJh3FZ2_lkFzepbkAAMQJYjR3Tw1KrbKAOzMxeE0F6QLcgDN8e/s1600/10.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" ru="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiwm1J_8B1TBlU-L-PiMMZG_0HGXFdJ6e4s9rsSdQ0xnTUZKtark0pZtiRC-8cA_M4F-6jZMDRqH6U_K1QhG19giHWBx8LJh3FZ2_lkFzepbkAAMQJYjR3Tw1KrbKAOzMxeE0F6QLcgDN8e/s320/10.jpg" /></a></div><div style="text-align: center;"><strong><em><span style="font-size: x-small;">PAVE PAWS phased array radar in Alaska.</span></em></strong></div><div style="text-align: justify;"><br />
Si todos los elementos del array están contenidos en el mismo plano y la señal con que se alimentan es de la misma fase, entonces se estará reforzando la dirección perpendicular a ese plano. Si se altera la fase relativa de las señales se podrá "mover" el haz (en realidad lo que se está haciendo es cambiar la dirección en la cual las interferencias son constructivas). Se consigue de este modo hacer barridos sin necesidad de movimiento físico, con la ventaja añadida de que se pueden escanear ángulos del orden de miles de grados por segundo. Esto permite utilizar la antena para compaginar simultáneamente funciones de detección y de seguimiento muchos blancos individuales. Apagando y encendiendo algunos de los elementos radiantes se puede variar el haz de radiación, ensanchándolo para mejorar las funciones de búsqueda o estrechándolo para hacer un seguimiento preciso de un objetivo. </div><div style="text-align: justify;"></div><div style="text-align: justify;"><br />
</div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjTMAkVh_vEhjWHf4wH82hGiBHEXcq6L58TxJLbqId4Z-E-yr_DPjihfFSUXeJJYyc0tJLp3tm8FcrT3cjYMaBrTj2DVhfoa7B_rRnpY436Kx-W2ZtFocFcPvb4GA-fiT4iPEE9DWqwMreW/s1600/11.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" ru="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjTMAkVh_vEhjWHf4wH82hGiBHEXcq6L58TxJLbqId4Z-E-yr_DPjihfFSUXeJJYyc0tJLp3tm8FcrT3cjYMaBrTj2DVhfoa7B_rRnpY436Kx-W2ZtFocFcPvb4GA-fiT4iPEE9DWqwMreW/s320/11.png" /></a></div><div class="separator" style="clear: both; text-align: center;"><strong><em><span style="font-size: x-small;">Modelo de phased array de la segunda guerra mundial.</span></em></strong></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">El punto débil de los phased arrays es la imposibilidad de dirigirlo correctamente en ángulos cercanos al plano en el que están los elementos radiantes. Para hacer una cobertura de 360º se suelen disponer 3 arrays en las paredes de una superficie piramidal (ver foto).</div><div align="justify" style="text-align: justify;"><br />
</div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjIRdouPNIoDVvrBOCGqemrU2uegcXwKl26dJZyrlQHu5oAB0sLeYFtBPOyovOzmw7LMDuPE_q_aLpLWxwBpurIgYQs631jLaBLYCrDI3mqIrn1GeM4VhD_UDE2de_tW3RrhXQ-T0OyBlkH/s1600/12.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" ru="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjIRdouPNIoDVvrBOCGqemrU2uegcXwKl26dJZyrlQHu5oAB0sLeYFtBPOyovOzmw7LMDuPE_q_aLpLWxwBpurIgYQs631jLaBLYCrDI3mqIrn1GeM4VhD_UDE2de_tW3RrhXQ-T0OyBlkH/s320/12.jpg" /></a></div><div class="separator" style="clear: both; text-align: center;"><em><strong><span style="font-size: x-small;">Base en Alaska de Cobra Dane</span></strong></em></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">El uso de los phased arrays se remonta a la Segunda Guerra Mundial, pero las limitaciones de la electrónica hacían que fueran poco precisos. Su aplicación original era la defensa antimisiles. En la actualidad son parte imprescindible del sistema AEGIS y el sistema balístico MIM-104 Patriot. Su uso se va extendiendo debido a la fiabilidad derivada del hecho de que no tienen partes móviles. Casi todos los radares militares modernos se basan en phased arrays, relegando los sistemas basados en antenas rotatorias a aplicaciones donde el costo es un factor determinante (tráfico aéreo, meteorología,...) Su uso está también extendido en aeronaves militares debido a su capacidad de seguir múltiples objetivos. El primer avión en usar uno fue el B-1B Lancer, y el primer caza, el MiG-31 ruso. El sistema radar de dicho avión está considerado como el más potente de entre todos los cazas.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">En radioastronomía también se emplean los phased arrays para, por medio de técnicas de apertura sintética, obtener haces de radiación muy estrechos. La apertura sintética se usa también en radares de aviones.</div><div style="text-align: justify;"><br />
</div><div style="text-align: center;"><strong><span style="font-size: large;">Uso de los phased array</span></strong></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;"><strong>Broadcasting (difusión)</strong></div><div style="text-align: justify;"></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">En ingeniería de difusión (broadcast),los phased arrays se usan en muchas estaciones de difusión AM por radio para mejorar la potencia de la señal y por lo tanto mejorar la cobertura ofrecida dentro del área establecida para la difusión, minimizando así las interferencias en otras áreas colindantes. Debido a la diferencia entre el día y la noche para la propagación de las ondas por la ionosfera a frecuencias medias, es muy común que las estaciones AM cambien de patrones de radiación utilizando unos para el día y otros para la noche mediante cambios en la fase y la potencia suministrados a los elementos radiantes de cada antena individual.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">En VHF, los phased arrays se usan por extensión para la difusión FM. De esta forma se consigue aumentar en gran medida la ganancia de la antena maximizando la energía de radiofrecuencia emitida hacia el horizonte lo que en consecuencia aumenta considerablemente el rango de difusión de la estación.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;"><strong>Uso Naval</strong></div><div style="text-align: justify;"><strong></strong><br />
Los sistemas de radar basados en phased array se usan en los barcos de guerra de diversas armadas como las de China, Noruega, Estados Unidos, España, etc . Los radares basados en phased arrays permiten a los barcos de guerra usar un radar para detección y búsqueda superficial (encontrando barcos), aérea (detectando misiles y aviones). Antes de usar estos sistemas, cada misil tierra-aire en vuelo necesitaba un radar de control dedicado, lo que significaba que los barcos podían únicamente tener localizados un pequeño número de objetivos. Dado que el haz del radar está dirigido electrónicamente, estos sistemas pueden dirigir las radiaciones del radar lo suficientemente rápido como para mantaner simultáneamente controlados numerosos objetivos, y a la vez, seguir controlando misiles en vuelo. Por ejemplo el radar AN/SPY-1, que pertenece al sistema Aegis combat system de los cruceros y destructores estadounidenses, "es capaz de realizar tareas de búsqueda, localización y guía de misiles simultáneamente de unos 100 objetivos" </div><div style="text-align: justify;"></div><div style="text-align: justify;"><br />
</div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh-ZLRAqZ_4Oo5ypz2fCmUSZfF4jhuJE3GrqId_gux4wbhKrD2NYBsre36034a4ggxHY7LtQ6neYaN9FeCLKwdr6iajZpL-xvEL9rvEVRa7ySlrdJ3ST3qa0COI2-6qJUvNAlr-MkTA_mi3/s1600/13.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" ru="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh-ZLRAqZ_4Oo5ypz2fCmUSZfF4jhuJE3GrqId_gux4wbhKrD2NYBsre36034a4ggxHY7LtQ6neYaN9FeCLKwdr6iajZpL-xvEL9rvEVRa7ySlrdJ3ST3qa0COI2-6qJUvNAlr-MkTA_mi3/s320/13.jpg" /></a></div><div class="separator" style="clear: both; text-align: center;"><strong><em><span style="font-size: x-small;">Paneles octogonales del radar phased array: AN/SPY-1D, del "USS Mason (DDG-87)".</span></em></strong></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;"><strong>Pruebas de comunicaciones espaciales</strong></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">La nave espacial MESSENGER , con misión hacia el planeta Mercurio, tiene prevista su llegada el 18 de marzo de 2011. Esta nave es la primera en ir a una misión al espacio lejano usando phased-array para telecomunicaciones.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;"><strong>Usos en climatología</strong></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;"></div><div style="text-align: justify;">El Laboratorio Nacional de tormentas severas ha estado usando una antena basada en phased array tipo SPY-1A procedente de la Armada de Estados Unidos para estudios climatológicos desde el 23 de abril de 2003. Mediante este tipo de estudios se logra una mejor comprensión de los tornados y tormentas, pudiendo así predecirlos con mayor margen de tiempo para tomar las precauciones pertinentes.</div><div style="text-align: justify;"></div><div style="text-align: justify;"><br />
</div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgqK7XrqEG1K9Ika-UjRb3daBKeGs61SQk_VvE_Hk-0A7beR2wXGpiYrSlPz04R8m2scxwnHgomMtwPjwVApHfXo2wXZdif_nvx4Pg5gN0dXDdmkyX7LoZv_SD7J6K3eCubF33tvtA0JgX_/s1600/14.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" ru="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgqK7XrqEG1K9Ika-UjRb3daBKeGs61SQk_VvE_Hk-0A7beR2wXGpiYrSlPz04R8m2scxwnHgomMtwPjwVApHfXo2wXZdif_nvx4Pg5gN0dXDdmkyX7LoZv_SD7J6K3eCubF33tvtA0JgX_/s320/14.jpg" /></a></div><div class="separator" style="clear: both; text-align: center;"><strong><em><span style="font-size: x-small;">Instalando el AN/SPY-1A en Norman, OK.</span></em></strong></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;"><strong>Comunicaciones ópticas</strong></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Es posible construir Phased arrays ópticos que emitan en las bandas visibles o infrarrojas. Estos phased arrays se usan en multiplexadores de longitud de onda , filtros para telecomunicaciones, direccionamiento de rayos láser, y holografía.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;"><strong>Identificaciones de radiofrecuencia</strong></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Las antenas basadas en phased array han sido incluidas recientemente en sistemas RFID para mejorar de forma significativa la capacidad lectora de las tarjetas pasivas de UHF que pasen de 20 a 600 pies.</div><div style="text-align: justify;"><br />
</div><div style="text-align: center;"><strong><span style="font-size: large;">Tipos de Phased Array</span></strong></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Hay numerosos tipos de Phased arrays. Básicamente:</div><div style="text-align: justify;"></div><div style="text-align: justify;"><ul><li>Phased arrays en el dominio temporal.</li>
<li>Phased arrays en el de la frecuencia </li>
</ul></div><br />
<div style="text-align: justify;">Un Phased arrays en el dominio del tiempo funciona mediante operaciones temporales. La operación básica se denomina "retarda y suma" (delay and sum). Funciona retardando la señal de entrada de cada array una cierta cantidad de tiempo, y después las suma todas. En ocasiones se multiplica el array por una ventana para incrementar el radio del lóbulo principal o de los laterales del diagrama de radiación, y para insertar ceros en las características.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Hay muchos tipos de phased arrays en el dominio de la frecuencia. El primer tipo separa componentes frecuenciales presentes en la señal recibida en diferentes haces usando filtros y FFT. Cuando se le aplican a cada componente frecuencial los diferentes retardos y sumas, es posible apuntar el lóbulo principal hacia diferentes direcciones para diferentes frecuencias, lo que es una gran ventaja para enlaces de comunicaciones.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Otro tipo de phased array hace uso de las denominadas frecuancias espaciales. Esto significa que se realiza una FFT entre los diferentes elementos del array, pero no al mismo tiempo. La salida de la FFT de N puntos son N canales que son divididos en espacio. Esta aproximación hace muy simple la implementación de diferentes phased array en el mismo tiempo, pero no es muy flexible porque sus direcciones de radiación son fijas.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;"><strong>Fuente: <a href="http://es.wikipedia.org/wiki/Phased_array">http://es.wikipedia.org/wiki/Phased_array</a></strong><strong></strong><br />
<strong>Ver blogger original:</strong> <a href="http://nubia-anc.blogspot.com/">http://nubia-anc.blogspot.com/</a></div><strong>Materia: CRF</strong>Nubia A. Navarro C.http://www.blogger.com/profile/16124874914747829398noreply@blogger.com0tag:blogger.com,1999:blog-5677235594720330703.post-19057161592912770812010-06-27T08:39:00.000-07:002010-06-27T08:39:48.188-07:00Antenas inteligentes o “smart antennas”<div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Son antenas que combinan múltiples elementos con un procesador de señal capaz de optimizar automáticamente la radiación o el patrón de recepción. Las hay de dos tipos:</div><div style="text-align: justify;"></div><div style="text-align: justify;"><br />
</div><ul><li><div style="text-align: justify;">Las de haz conmutado, con un número finito de patrones predefinidos o estrategias de combinación (Antenas sectoriales) o</div></li>
<li><div style="text-align: justify;">Las de arrays adaptativos o configuración de haz, más avanzadas, que cuentan con un número infinito de patrones de iluminación (dependiendo del escenario) y ajustan el diagrama radiante y los nulos en tiempo real.</div></li>
</ul><div style="text-align: justify;"> </div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj2MxfFJ2gByrfmMfDzv_fCZA_z1C4RrpsEOodR1DI0HHetBV8BRNtxw-fw7JYDdfrHIePJVeGLxdqfwmexqzaLTCRdRwj9IQyR-IduRsHGq5sa2JDlX1CzLwxUZOKe0R4h_rtF861Wo0L5/s1600/4.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" ru="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj2MxfFJ2gByrfmMfDzv_fCZA_z1C4RrpsEOodR1DI0HHetBV8BRNtxw-fw7JYDdfrHIePJVeGLxdqfwmexqzaLTCRdRwj9IQyR-IduRsHGq5sa2JDlX1CzLwxUZOKe0R4h_rtF861Wo0L5/s320/4.png" /></a></div><div class="separator" style="clear: both; text-align: center;"><strong><em><span style="font-size: x-small;">Antena sectorial (izquierda) versus antena inteligente de configuración de haz (derecha)</span></em></strong> </div><div style="text-align: justify;"></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Las antenas de arrays adaptativos mejoran la recepción de la señal y minimizan las interferencias, dando una ganancia mejor que las antenas convencionales. Este tipo de antenas permiten direccionar el haz principal, y/o configurar múltiples haces, así como generar nulos del diagrama de radiación en determinadas direcciones que se consideran interferentes.Con ello se aumenta la calidad de la señal y se mejora la capacidad por la reutilización de frecuencias. Son aplicables a casi todos los protocolos y estándares inalámbricos (comunicaciones móviles, WLL, WLAN, satélite, etc.).</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Es una tecnología con un excelente potencial para aumentar la eficacia del uso del espectro en comparación con los sistemas radiantes tradicionales. Con un control inteligente de la iluminación de la antena se puede ampliar la capacidad y la cobertura de las redes móviles.</div><div style="text-align: justify;"><br />
</div><div style="text-align: center;"><strong>Antenas Adaptativas: Analogía con el oído y cerebro humano</strong></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">El siguiente ejemplo le ayudará a entender cómo funciona una antena adaptativa. Cierre los ojos e inicie una conversación con alguien que se mueva por la habitación donde están ustedes dos. A pesar de tener los ojos cerrados, le resultará sencillo saber por donde se mueve el otro interlocutor, por lo siguiente:</div><div style="text-align: justify;"><br />
</div><ul><li><div style="text-align: justify;">Vd. está oyéndole por medio de dos oídos que son sus sensores acústicos.</div></li>
<li><div style="text-align: justify;">La voz llega a cada oído por distinto camino (diversidad de espacio), por tanto los sonidos no llegan a los dos oídos a la vez. Casi siempre habrá una pequeña diferencia.</div></li>
<li><div style="text-align: justify;">Su cerebro es un procesador de señal muy especial, sin que Vd. se de cuenta está realizando una gran cantidad de cálculos para determinar la posición de la otra persona.</div></li>
<li><div style="text-align: justify;">Su cerebro, además, suma las señales de los dos oídos, de modo que el sonido que le llega de la orientación del interlocutor es el doble de intenso del que le llega de otras zonas.</div></li>
</ul><div style="text-align: justify;">Las antenas adaptativas hacen lo mismo, con antenas en vez de oidos. Incluso pueden tener 8, 10 o 12 oídos para ser más precisas. Y como además de recibir sirven para emitir, un sistema adaptativo puede ajustar el patrón de emisión para que ilumine hacia la misma dirección de donde recibe. Por tanto, ese sistema además de “recibir” 8, 10 o 12 veces más fuerte también puede “emitir” más fuerte y con mayor directividad.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Demos un paso más con este ejemplo; si entrasen más personas a la habitación, su procesador de señal (su cerebro) ignoraría el ruido producido por las otras conversaciones, las que no quiere escuchar (las interferencias), para enfocar su antención en la conversación deseada. De manera similar un sistema adaptativo con un procesador adecuado puede diferenciar entre las señales deseadas y las no deseadas.</div><div style="text-align: justify;"><br />
</div><div style="text-align: center;"><strong>Multiplexación en código: Analogía con el oído y cerebro humano</strong></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Al hilo del ejemplo anterior, aprovecharemos para presentar otro caso que está indirectamente relacionado con las antenas inteligentes: imagine ahora que está en el extranjero en un local lleno de gente, bastante ruidoso por cierto, donde la mayoría de las personas están hablando en el idioma local.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">¿No cree le resultará bastante fácil percatarse de alguna conversación que se esté manteniendo en medio de aquel ruido en el idioma de su país, en su idioma materno?</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Podríamos decir que las conversaciones de ese local está multiplexadas en código, y que Vd., su cerebro, tiene un procesador de señal con la clave adecuada para distinguir las de su idioma.</div><div style="text-align: justify;"><br />
</div><div style="text-align: center;"><strong>MIMO </strong></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhVkSFulTMDn87l2RwcRlPe4-gfF3M7AOQVd37oE7HgZzlq-cMRwLfb9f4wMS6CyDxI3L3_l3DgXJ991b_TSJKlqK8GzGMBG8RoPvodgikJvmCySnkIhVb8zd9ZSewioS1hdLC56NDFnueS/s1600/5.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" ru="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhVkSFulTMDn87l2RwcRlPe4-gfF3M7AOQVd37oE7HgZzlq-cMRwLfb9f4wMS6CyDxI3L3_l3DgXJ991b_TSJKlqK8GzGMBG8RoPvodgikJvmCySnkIhVb8zd9ZSewioS1hdLC56NDFnueS/s320/5.jpg" /></a></div><div style="text-align: justify;"> </div><div style="text-align: justify;"><em><strong>Concepto MIMO</strong></em> </div><div style="text-align: justify;"></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Multiple-Input Multiple-Output o MIMO (en castellano « entradas múltiples, salidas múltiples ») es una tecnología de antenas inteligentes de arrays adaptativos empleada en algunas redes inalámbricas como, por ejemplo, en femtoceldas y en WiMAX que aprovecha el fenómeno de multipropagación y radiocomunicaciones en diversidad de espacio para conseguir una mayor velocidad y un mejor alcance del que se consigue con las antenas tradicionales.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">La tecnología MIMO emplea varias antenas tanto en el transmisor como en el receptor, y para un mismo ancho de banda y potencia transmitida consigue mejores resultados que los sistemas SISO (single-input single-output). La capacidad de un sistema MIMO en un entorno de dispersión por multipropagación, cuando las señales recibidas no están correlacionadas entre sí, es proporcional al número de antenas empleadas. El diseño de las antenas y el proceso de la señal recibida necesita técnicas especializadas.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">El diseño de las antenas MIMO buscar reducir la correlación entre las señales recibidas, para ello utiliza los diferentes modos de diversidad que se pueden dar en la recepción, como la diversidad de espacio (al estar las antenas separadas), la diversidad de ganancia (por emplear antenas con diferentes patrones de radiación, ortogonales u otros) y la diversidad de polarización (antenas con distinta polarización) etc. Estas tres formas de diversidad se muestran el la figura siguiente.</div><div style="text-align: justify;"><br />
</div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgIwRil4VADJiNyGAseHV3kL5dHTCJg-fUIZa3tiW6cut_3NFpRxHBbdV5YDWVHfc3NyUrlthYXZof3YlyENt3k4ie30qgt6ZUtNDP7dor2Nmf2WxkOKdIoYVBi2m5BVutDKPXql28zWTBE/s1600/6.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" ru="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgIwRil4VADJiNyGAseHV3kL5dHTCJg-fUIZa3tiW6cut_3NFpRxHBbdV5YDWVHfc3NyUrlthYXZof3YlyENt3k4ie30qgt6ZUtNDP7dor2Nmf2WxkOKdIoYVBi2m5BVutDKPXql28zWTBE/s320/6.jpg" /></a></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;"><strong><em>Variantes de la tecnología MIMO</em></strong> </div><div style="text-align: justify;"></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;"><strong><em>MIMO:</em></strong> Multiple input multiple output; este es el caso en el que tanto transmisor como receptor tienen varias antenas.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;"><em><strong>MISO:</strong></em> Multiple input Single output; en el caso de que haya varias antenas de emisión pero solamente una en el receptor.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;"><em><strong>SIMO:</strong></em> Single input multiple output; en el caso de una sola antena de emisión y varias antenas en el receptor.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">En función de las tres variantes citadas se empleará una u otra de las siguientes tecnologías:</div><div style="text-align: justify;"><br />
</div><ul><li><div style="text-align: justify;"><strong>Configuración de Haz (Beamforming):</strong> Consiste en la formación de un patrón de iluminación bien determinado, fruto del desfase de la señal en las distintas antenas. Sus principales ventajas son una mayor ganancia de señal además de una menor atenuación con la distancia. Gracias a la ausencia de dispersión el beamforming consigue un patrón bien definido y direccional. En este tipo de transmisiones se hace necesario el uso de dominios de configuración de haz, sobre todo en el caso de múltiples antenas de transmisión. Hay que tener en cuenta que esta técnica precisa un conocimiento previo del canal a utilizar en el transmisor.</div></li>
<li><div style="text-align: justify;"><strong>Multiplexación espacial (Spatial multiplexing):</strong> Consiste en la multiplexación de una señal de mayor ancho de banda en señales de menor ancho de banda iguales transmitidas desde distintas antenas. Si estas señales llegan con la suficiente separación en el tiempo al receptor este es capaz de procesarlas y distinguirlas creando así múltiples canales en anchos de banda mínimos. Esta técnica es eficaz para aumentar la tasa de transmisión, sobre todo en entornos difíciles en cuanto a la relación señal ruido. Únicamente está limitado por el número de antenas disponibles tanto en receptor como en transmisor. No requiere el conocimiento previo del canal en el transmisor o receptor. Para este tipo de transmisiones es obligatoria una configuración de antenas MIMO.</div></li>
<li><div style="text-align: justify;"><strong>Diversidad de código (Code-division multiple access):</strong> Son una serie de técnicas que se emplean en medios en los que por alguna razón solo se puede emplear un único canal, codificando la transmisión mediante espaciado en el tiempo y la diversidad de señales disponibles dando lugar al código espacio-tiempo. Para aumentar la diversidad de la señal se recurre a una emisión desde varias antenas basándose en principios de ortogonalidad.</div></li>
</ul><div style="text-align: justify;">La multiplexación de espacio puede ser combinada con la configuración de haz cuando el canal es conocido en el transmisor o combinado con la diversidad de código cuando no es así. La distancia física entre las antenas ha de ser múltiples longitudes de onda en la estación base. Para poder distinguir las señales con claridad, la separación de las antenas en el receptor tiene que ser de al menos 0,3 λ.</div><div style="text-align: justify;"><br />
</div><div style="text-align: center;"><strong>Aprovechamiento de la diversidad de espacio</strong></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">En un sistema de comunicaciones es básico poder distinguir los usuarios. Los sistemas de acceso múltiple más usuales son la multiplexación en frecuencia (frequency division multiple access, FDMA), la multiplexación en tiempo (time-division multiple access, TDMA) y la la multiplexación en código (code-division multiple access, CDMA). Estás técnicas separan los usuarios según la frecuencia, el tiempo y el código, respectivamente, y proporcionan tres tipos de diversidad.</div><div style="text-align: justify;"> </div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgQDHsb7xRAtAQj68pZmYz5XIjDWXPKVI8KdN_2kztdmk1MZW4buE5E7m-DxM9mchLOe14ODiGLHVUnBq-5sIEfEVebtDRYETZq2U0xMrv3EPpkADi-X03FXloB40kgihMpXrfC0wlPe2Yv/s1600/7.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" ru="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgQDHsb7xRAtAQj68pZmYz5XIjDWXPKVI8KdN_2kztdmk1MZW4buE5E7m-DxM9mchLOe14ODiGLHVUnBq-5sIEfEVebtDRYETZq2U0xMrv3EPpkADi-X03FXloB40kgihMpXrfC0wlPe2Yv/s320/7.png" /></a></div><div style="text-align: center;"><strong><em><span style="font-size: x-small;">Figura 1 TDMA (izda.), FDMA (centro), CDMA (dcha.)</span></em></strong> </div><div style="text-align: justify;"></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Una antena inteligente puede reducir las interferencias empleando diversidad de espacio (que se suele denominar en inglés como spatial diversity o SDMA) y en consecuencia aumentar la capacidad de comunicación adaptando dinámicamente las características del sistema radiante. Concretamente, concentra y dirige el haz al usuario, consiguiendo mayor eficacia que una antena sectorial y mejorando el comportamiento ante interferencias.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Patrones de iluminación – Configuración de haz</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Un sistema radiante con elementos en fase está formado por un conjunto de elementos radiantes cuyas señales se suman y forman un determinado patrón de radiación o iluminación. Cambiando la amplitud y fase de los elementos individuales se puede modificar la forma del patrón de iluminación, fenómeno que se conoce como “confifuración de haz” (o beamforming process en inglés).</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">En este tipo de sistemas radiantes se busca tener el máximo de señal en la dirección deseada, y simultáneamente conseguir “nulos” en la dirección de las emisiones indeseadas. Por tanto, la antena se puede ajustar para que tenga una alta sensibilidad a las señales de un determinado usuario y que tenga menos a las de otros usuarios.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Las antenas inteligentes que estamos tratando en este artículo incorporan unos procesadores para poder de variar dinámicamente el patron radiante.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Una de los entidades reguladoras nacionales (ANR) que más esfuerzos de investigación y pruebas ha dedicado a estas técnicas es Ofcom, que ya en 2003 construyó un prototipo de sistema WiFi, IEE 802.11a con antena inteligente, que se muestra en la imagen siguiente.</div><div style="text-align: justify;"><br />
</div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEit82MXDxboZqQpvoTLn5VtiAEvMxySvNUCrDBgZyyLoIeRjqBlM9nSGxXa-7-2ipr3vydc1-4ZZAtf6P3WrF8aI4bhsPZCS9KD1YU0XtJMxE8BBe4a47KRu5XkEFTWeo_2r9Sau7wM7zFA/s1600/8.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" ru="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEit82MXDxboZqQpvoTLn5VtiAEvMxySvNUCrDBgZyyLoIeRjqBlM9nSGxXa-7-2ipr3vydc1-4ZZAtf6P3WrF8aI4bhsPZCS9KD1YU0XtJMxE8BBe4a47KRu5XkEFTWeo_2r9Sau7wM7zFA/s320/8.jpg" /></a><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhK9gZOHIxr67ziBXACwsI2y-vTIHNpE5lIYxgCiXy4G8HcVg1UauyAvtUGvJIPO3RS6gzwhMmRO9W1ywLZWdW7vV4-_Mmi_NzKTfKjtBzzZt9Nu8PAkvSGmF8IKP6OqOexJ8iFF39fiXLX/s1600/9.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" ru="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhK9gZOHIxr67ziBXACwsI2y-vTIHNpE5lIYxgCiXy4G8HcVg1UauyAvtUGvJIPO3RS6gzwhMmRO9W1ywLZWdW7vV4-_Mmi_NzKTfKjtBzzZt9Nu8PAkvSGmF8IKP6OqOexJ8iFF39fiXLX/s320/9.jpg" /></a></div><div style="text-align: center;"><em><strong>Prototipo de punto de acceso 802.11a con antena adaptativa semi-inteligente y procesador</strong></em></div><div style="text-align: justify;"></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;"><strong>Fuente:</strong> <a href="http://jrojo.wordpress.com/2010/02/19/antenas-inteligentes-o-smart-antennas/">http://jrojo.wordpress.com/2010/02/19/antenas-inteligentes-o-smart-antennas/</a></div><div style="text-align: justify;"><strong>Ver blogger original:</strong> <a href="http://nubia-anc.blogspot.com/">http://nubia-anc.blogspot.com/</a></div><div style="text-align: justify;"><strong>Materia: CRF</strong></div>Nubia A. Navarro C.http://www.blogger.com/profile/16124874914747829398noreply@blogger.com0tag:blogger.com,1999:blog-5677235594720330703.post-58546562845920515462010-06-27T08:18:00.000-07:002010-06-27T08:18:53.783-07:00URI physics employee invents new antenna technology<div style="text-align: justify;"><br />
</div><div style="text-align: justify;">KINGSTON, R.I. -- June 2, 2004 -- Rob Vincent, an employee in the University of Rhode Island's Physics Department, proves the adage that necessity is the mother of invention. </div><div style="text-align: justify;"></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">An amateur radio operator since he was 14, Vincent has always lived in houses situated on small lots. Because he couldn’t erect a large antenna on a confined property, he has been continually challenged over the years to find a way to get better reception. </div><div style="text-align: justify;"><br />
</div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjVC5Ix-Xtu4EMdd68g8c7c0SjHZTB-KwiGRoKIBiCqP-WUk8bup1dUISh7OXq8Zn3_xEh6nNDIkgK89KS3l0rH-TaFkajR6lH6ZOuofjf7VoS_MO1rFKOHcwKzITnv2_ayf3rWRnzmTRr6/s1600/3.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" ru="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjVC5Ix-Xtu4EMdd68g8c7c0SjHZTB-KwiGRoKIBiCqP-WUk8bup1dUISh7OXq8Zn3_xEh6nNDIkgK89KS3l0rH-TaFkajR6lH6ZOuofjf7VoS_MO1rFKOHcwKzITnv2_ayf3rWRnzmTRr6/s320/3.jpg" /></a></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">"I was always tinkering in the basement. Thank goodness, my parents were tolerant. I can still remember my poor father driving up our driveway after a hard day’s work to see wires wrapped around the house," Vincent recalls.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">"The Holy Grail of antenna technology is to create a small antenna with high efficiency and wide bandwidth," explains Vincent. "According to current theory, you have to give up one of the three—size, efficiency, or bandwidth—to achieve the other two."</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">After decades of experimentation, combined with a 30-year engineering career and Yankee ingenuity, Vincent has invented a revolutionary antenna technology. The distributed- load, monopole antennas are smaller, produce high efficiency, and retain good to excellent bandwidth. And they have multiple applications.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">With this technology it will be possible to double, at minimum, the range of walkie-talkies used by police, fire, and other municipal personnel. Naval ships, baby monitors, and portable antennas for military use are other applications. An antenna could be mounted on a chip in a cell phone and be applied to wireless local area networks. Another application deals with radio frequency identification, which is expected someday to replace the barcode system.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">"It could even make the Dick Tracy wrist radio with all the features, such as Internet access, a possibility," Vincent says.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">The inventor pursued his quest to build a better antenna in earnest eight years ago when he and his significant other moved into a house situated on a 50-foot by 100-foot lot in Warwick. There was nothing on the commercial market that could fit the lot that would provide the performance Vincent needed to be heard in distant lands and that would be acceptable to his neighbors. All the small antennas being sold were inefficient and lacked bandwidth, which resulted in low performance and high frustration.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Vincent looked at the techniques that were currently used to reduce antenna size and realized something was missing in the way everyone was approaching the problem.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">He began to model various combinations into a computer program called MathCad. His first attempt produced a 21 MHz band antenna that was 18 inches high. Normally, antennas for this band are 12 to 24 feet high. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Vincent installed the antenna in his back yard. The legal limit that amateurs can operate is 1,000 watts with the norm being 100 watts. The amateur radio operator experimented with 5 to 10 watts. He reached a station in Chile and made contacts in various European countries. Meanwhile he kept adding power until it reached 100 watts. That’s when things suddenly went bad. Walking outside in the backyard, he understood why. The antenna had melted. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">After examining the molten matter, Vincent wasn’t discouraged. This was only a small model and not designed to handle much power. The part of the antenna that failed proved to be the key to the design. After analyzing the failure, Vincent realized that he was able to transform a lot of current along the antenna with even relatively low power. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">"Antennas radiate by setting up large amounts of current flow through various parts of their structure," he says. "The larger the current the more radiation and the better the output of the antenna."</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Vincent went back to the drawing board and continued to improve the technology. Relying on his nearly 30 years at Raytheon Co. and at KVH Industries in Middletown R.I., which provided him with a diversified background in electronics and electronic systems, Vincent overcame a myriad of problems and succeeded.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">He established three test sites for various prototypes. Antennas were placed in Westport, Mass. in a salt marsh, the best ground for transmission and reception. Another set of antennas was placed on rocky ground in Cumberland, R.I., the worst kind of site, and at a Warwick site which is in between the two in terms of grounding. The antennas, which resemble flagpoles, worked well at all locations. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Tests confirmed that Vincent has created antennas at one third to one ninth of their full size counterparts. Normally smaller antennas are only 8 to 15 percent efficient. Vincent’s antennas achieved 80 to 100 percent efficiency as compared to the larger antennas.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">A patent is pending on Vincent's technology. The inventor has made the University of Rhode Island and its Physics Department partners that will benefit from any revenue his invention earns. "The University and its Physics Department has been very supportive and given me time and space to work on this project," says Vincent who was recently presented the 2004 Outstanding Intellectual Property Award by URI's Research Office. "I couldn't have done this without the University's support. It's only fair that it share in the profits."</div><div style="text-align: justify;"><br />
</div><strong>Fuente:</strong> <a href="http://www.uri.edu/news/releases/?id=2659">http://www.uri.edu/news/releases/?id=2659</a><br />
<strong>Ver blogger original</strong>: <a href="http://nubia-anc.blogspot.com/">http://nubia-anc.blogspot.com/</a><br />
<strong>Materia: CRF</strong>Nubia A. Navarro C.http://www.blogger.com/profile/16124874914747829398noreply@blogger.com0tag:blogger.com,1999:blog-5677235594720330703.post-66405027290202926202010-06-27T08:08:00.000-07:002010-06-27T08:08:12.959-07:00MTI Wireless Edge picks up major order for military antennas<div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Mti Wireless Edge (LON:MWE), the AIM listed technology group that makes flat panel antennas for fixed wireless broadband, has picked up a US$2.2m order from an existing client to develop and manufacture military antennas. Deliveries of the new units will span two years and approximately US$0.5m is expected to be recognised as revenue in 2010.</div><div style="text-align: justify;"></div><div style="text-align: justify;"><br />
</div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgvDcKlnDR9X5_SD2rVZnpbLzWGMRufdQR1UYBYPmtG95QZ047uOshbHhv3nsBQK40_xVDjVZCyxAG8_TP-QJxK6ws7rUghgaJDbSvbceiQ5rKFl7zfvnwcVJPRVJ4C0Ft29Th8rSY0iiRP/s1600/2.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" ru="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgvDcKlnDR9X5_SD2rVZnpbLzWGMRufdQR1UYBYPmtG95QZ047uOshbHhv3nsBQK40_xVDjVZCyxAG8_TP-QJxK6ws7rUghgaJDbSvbceiQ5rKFl7zfvnwcVJPRVJ4C0Ft29Th8rSY0iiRP/s320/2.jpg" /></a></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Dov Feiner, MTI’s chief executive, said: “We are delighted with this order for military antennas. It provides an important revenue stream for us, as well as involvement in the forefront of antenna technology. As leaders in our field, we are the only company with the technical expertise and capability to provide high specification products for military application as well as industry leading antennas for the commercial, high volume market.”</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Israel-based MTI makes industry-unique, flat panel antennas for commercial applications, fixed wireless and RFID readers as well as military antenna solutions spanning the entire radio frequency range (2MHz-40GHz). The company disappointed investors in May by announcing a 17% fall in revenues to US$2.8m in the three months to March and an operating loss of US$0.5m. At the time it blamed a late influx of late orders during the quarter and said the revenue had simply been delayed rather than lost. In the year to December 2009, revenues fell by 25% to US$13.5m and the company hit breakeven after posting a US$1m profit the year before. It claimed that market shrinkage and increasing competition during 2009 had created a more difficult trading environment.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;"><strong>Fuente:</strong> <a href="http://www.stockopedia.co.uk/content/mti-wireless-edge-picks-up-major-order-for-military-antennas/43092">http://www.stockopedia.co.uk/content/mti-wireless-edge-picks-up-major-order-for-military-antennas/43092</a></div><div style="text-align: justify;"><strong>Ver blogger original:</strong> <a href="http://nubia-anc.blogspot.com/">http://nubia-anc.blogspot.com/</a></div><div style="text-align: justify;"><strong>Materia: CRF</strong></div>Nubia A. Navarro C.http://www.blogger.com/profile/16124874914747829398noreply@blogger.com0tag:blogger.com,1999:blog-5677235594720330703.post-89548053634669077522010-06-27T08:02:00.000-07:002010-06-27T08:12:35.951-07:00New Report: Mobile Patents and Intellectual Property Rights<div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Femtocells and Wi-Fi oriented fixed/mobile solutions are both important for improving wireless services in rural areas, but they rely on availability of decent quality DSL or cable lines for backhaul. But many parts of the world, including regions of Europe and north America plus emerging economies, remain underserved by wired infrastructure. A UK start-up today launches a response to that challenge, a self-installed wireless router backhauled by the cellular network and using innovative antenna technology to optimize the signal.</div><div style="text-align: justify;"></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">The WiBE (Wireless Broadband Enabler) from Deltenna is targeted mainly at rural areas with little or poor quality DSL, though it could also be used to improve indoor reception for urban users. Its supplier, a specialist in antennas and their integration with radio systems, promises a reliable 2Mbps connection for users far from the DSL exchange. It also pledges sustained data throughput at 30 times the rate, and five times the range, of a 3G dongle in areas where signal quality is poor. These USB modems have been widely touted as a solution to rural broadband, and are marketed by some cellcos, even in well-served regions, as a lower cost alternative to a DSL line, but remain less reliable than a wired option.</div><div style="text-align: justify;"><br />
</div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhOdzlI6d3yIWDGCfU9WaxH0Cck7Cf6M9WvJiz_f3_Z6ZcwSKqFoXDtyIdjVX2IeJPeY9N67ZFIL7m5oyPePwR5qoFYYU5xFVKW5k8yLMYWbjWs2ckHJCNjLLgcuLYAHzopOmZZ7RKUxMvM/s1600/1.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" ru="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhOdzlI6d3yIWDGCfU9WaxH0Cck7Cf6M9WvJiz_f3_Z6ZcwSKqFoXDtyIdjVX2IeJPeY9N67ZFIL7m5oyPePwR5qoFYYU5xFVKW5k8yLMYWbjWs2ckHJCNjLLgcuLYAHzopOmZZ7RKUxMvM/s320/1.jpg" /></a></div><div style="text-align: justify;"><br />
The WiBE is designed to be plug-and-play, and once installed, creates a 2Mbps Wi-Fi hotspot within the home or office, backhauled by 3G. The directional antenna technology achieves average download speed of 2.8Mbps over the HSPA network when a conventional handset or dongle can scarcely register a signal, the company claims after tests in rural UK. Deltenna has patented antenna technology and alignment algorithms, which enable the WiBE to identify the cell that will support the best available download speed, and configure itself automatically to focus on that cell.</div><div style="text-align: justify;"></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">The WiBE will be sold to OEMs and operators, targeting rural and emerging economy carriers. An LTE version is in development and will be announced next year, promising rural broadband speeds of 50Mbps. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Andrew Fox, CEO of Deltenna, said: "There are still millions of people throughout Europe and the US for whom fast broadband is a myth."</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Iain Wood, of broadband benchmarking organization Epitiro, commented: "Rural broadband consumers in Europe and the US suffer low speeds over copper wiring as a result of being a long distance from the exchange. This challenge of achieving higher speeds lies with the implementation of new technologies to the last mile, be they wired or wireless." However, Eptiro finds that phones and dongles typically achieve only 1Mbps in rural HSPA networks.</div><br />
<strong>Fuente</strong>: <a href="http://www.rethink-wireless.com/2010/06/22/uk-start-up-promises-rural-broadband-dsl.htm">http://www.rethink-wireless.com/2010/06/22/uk-start-up-promises-rural-broadband-dsl.htm</a> <br />
<strong>Ver blogger original</strong>: <a href="http://nubia-anc.blogspot.com/">http://nubia-anc.blogspot.com/</a> <br />
<strong>Materia: CRF</strong>Nubia A. Navarro C.http://www.blogger.com/profile/16124874914747829398noreply@blogger.com0tag:blogger.com,1999:blog-5677235594720330703.post-13993902032712232192010-05-30T18:05:00.000-07:002010-05-30T18:09:25.885-07:00RF MEMS<div style="text-align: justify;"><br />
The RF MEMS acronym stands for radio frequency microelectromechanical system, and refers to components of which moving sub-millimeter-sized parts provide RF functionality. RF functionality can be implemented using a variety of RF technologies. Besides RF MEMS technology, ferrite, ferroelectric, GaAs, GaN, InP, RF CMOS, SiC, and SiGe technology are available to the RF designer. Each of the RF technologies offers a distinct trade-off between cost, frequency, gain, large scale integration, lifetime, linearity, noise figure, packaging, power consumption, power handling, reliability, repeatability, ruggedness, size, supply voltage, switching time and weight.</div><div style="text-align: justify;"><br />
</div><div style="text-align: center;"><strong><em><span style="font-size: large;">Components</span></em></strong></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">There are various types of RF MEMS components, such as RF MEMS resonators and self-sustained oscillators with low phase noise, RF MEMS tunable inductors, and RF MEMS switches, switched capacitors and varactors.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;"></div><div style="text-align: justify;"><strong><em>Resonators</em></strong></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;"></div><div style="text-align: justify;">More to come.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;"><em><strong>Switches, switched capacitors and varactors</strong></em></div><div style="text-align: justify;"></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">RF MEMS switches, switched capacitors and varactors, which can replace field effect transistor (FET) switches and PIN diodes, are classified by actuation method (electrostatic, electrothermal, magnetic, piezoelectric), by axis of deflection (laterally, vertically), by circuit configuration (series, shunt), by clamp configuration (cantilever, fixed-fixed beam), or by contact interface (capacitive, ohmic). Electrostatically-actuated RF MEMS components offer low insertion loss and high isolation, high linearity, high power handling and high Q factor, do not consume power, but require a high supply voltage and hermetic wafer level packaging (WLP) (anodic or glas frit wafer bonding) or single chip packaging (SCP) (thin film capping, liquid crystal polymer (LCP) or low temperature co-fired ceramic (LTCC) packaging).</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">RF MEMS switches were pioneered by Hughes Research Laboratories, Malibu, CA, Raytheon, Dallas, TX, and Rockwell Science, Thousand Oaks, CA, during the nineties. The component shown in Fig. 1, is a center-pulled capacitive fixed-fixed beam RF MEMS switch, developed and patented by Raytheon in 1994. A capacitive fixed-fixed beam RF MEMS switch is in essence a micro-machined capacitor with a moving top electrode - i.e. the beam.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;"><br />
</div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj59Q-UJ-6w60eD8zQGI0lhNT_yShyphenhyphenfe522QiZw1AqNh69uFPT-AJQigTQ8tdjfphWksQCTQE5ZxE2e5gxrLSodGoHmR2Sbm9VpQ70wLTVXCtVox_7kBYaGkz6Q7j9EbzGg6ayHDtg-lwXK/s1600/ii1.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" gu="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj59Q-UJ-6w60eD8zQGI0lhNT_yShyphenhyphenfe522QiZw1AqNh69uFPT-AJQigTQ8tdjfphWksQCTQE5ZxE2e5gxrLSodGoHmR2Sbm9VpQ70wLTVXCtVox_7kBYaGkz6Q7j9EbzGg6ayHDtg-lwXK/s320/ii1.png" /></a></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">From an electromechanical perspective, the components behave like a mass-spring system, actuated by an electrostatic force. The spring constant is a function of the dimensions of the beam, of the Young's modulus, of the residual stress and of the Poisson ratio of its material. The electrostatic force is a function of the capacitance and the bias voltage. Knowledge of spring constant and mass allows for calculation of the pull-in voltage, which is the bias voltage necessary to pull-in the beam, and of the switching time.</div><div style="text-align: justify;"></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">From an RF perspective, the components behave like a series RLC circuit with negligible resistance and inductance. The up- and down-state capacitance are in the order of 50 fF and 1.2 pF, which are functional values for millimeter-wave circuit design. Switches typically have a capacitance ratio of 30 or higher, while switched capacitors and varactors have a capacitance ratio of about 1.2 to 10. The loaded Q factor is between 20 and 50 in the X-, Ku- and Ka-band.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">RF MEMS switched capacitors are capacitive fixed-fixed beam switches with a low capacitance ratio. RF MEMS varactors are capacitive fixed-fixed beam switches which are biased below pull-in voltage. Other examples of RF MEMS switches are ohmic cantilever switches, and capacitive single pole N throw (SPNT) switches based on the axial gap wobble motor.</div><div style="text-align: justify;"><br />
</div><div style="text-align: center;"><strong><em><span style="font-size: large;">Microfabrication</span></em></strong></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">An RF MEMS fabrication process allows for integration of SiCr or TaN thin film resistors (TFR), metal-air-metal (MAM) capacitors, metal-insulator-metal (MIM) capacitors, and RF MEMS components. An RF MEMS fabrication process can be realized on a variety of wafers: fused silica (quartz), borosilicate glass, LCP, sapphire, and passivated silicon and III-V compound semiconducting wafers. As shown in Fig. 2, RF MEMS components can be fabricated in class 100 clean rooms using 6 to 8 optical lithography steps with a 5 μm contact alignment error, whereas state-of-the-art monolithic microwave integrated circuit (MMIC) and radio frequency integrated circuit (RFIC) fabrication processes require 13 to 25 lithography steps. The essential microfabrication steps are:</div><div style="text-align: justify;"><ul><li>Deposition of the bias lines (Fig. 2, step 3)</li>
<li>Deposition of the electrode layer (Fig. 2, step 4) </li>
<li>Deposition of the dielectric layer (Fig. 2, step 5) </li>
<li>Deposition of the sacrificial spacer (Fig. 2, step 6) </li>
<li>Deposition of seed layer and subsequent electroplating (Fig. 2, step 7) </li>
<li>Beam definition, release and critical point drying (Fig. 2, step 8)</li>
</ul></div><br />
<div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh9MsZH8Hwshc6TtsnAl6lwZhu5G1eAFf7BBG-9e61jPTY9Y3veQ5eNMnW6d52cl2CbePwDGDcS8nNH2XMfZX4nATw-CUZzKFit-n6Rn2zrwd_NXhX81qIdv7jJPaOIhQ4mFvBlr2olD0n9/s1600/ii2.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" gu="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh9MsZH8Hwshc6TtsnAl6lwZhu5G1eAFf7BBG-9e61jPTY9Y3veQ5eNMnW6d52cl2CbePwDGDcS8nNH2XMfZX4nATw-CUZzKFit-n6Rn2zrwd_NXhX81qIdv7jJPaOIhQ4mFvBlr2olD0n9/s320/ii2.jpg" /></a></div><div class="separator" style="clear: both; text-align: center;"><br />
</div><div style="text-align: justify;">RF MEMS fabrication processes, unlike barium strontium titanate (BST) or lead zirconate titanate (PZT) ferroelectric and MMIC fabrication processes, do not require electron beam lithography, molecular beam epitaxy (MBE), or metal organic chemical vapor deposition (MOCVD). With the exception of the removal of the sacrificial spacer, the fabrication steps are compatible with a CMOS fabrication process.</div><div style="text-align: justify;"><br />
</div><div style="text-align: center;"><em><strong><span style="font-size: large;">Applications</span></strong></em></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Applications of RF MEMS resonators and switches include oscillators and routing networks. RF MEMS components are also applied in radar sensors (passive electronically scanned (sub)arrays and T/R modules) and software-defined radio (reconfigurable antennas, tunable band-pass filters).</div><div style="text-align: justify;"></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;"><strong><em>Antennas</em></strong></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Polarization and radiation pattern reconfigurability, and frequency tunability, are usually achieved by incorporation of lumped components based on III-V semiconductor technology, such as single pole single throw (SPST) switches or varactor diodes. However, these components can be readily replaced by RF MEMS switches and varactors in order to take advantage of the low insertion loss and high Q factor offered by RF MEMS technology. In addition, RF MEMS components can be integrated monolithically on low-loss dielectric substrates, such as borosilicate glass, fused silica or LCP, whereas III-V semiconducting substrates are generally lossy and have a high dielectric constant. A low loss tangent and low dielectric constant are of importance for the efficiency and the bandwidth of the antenna.</div><div style="text-align: justify;"></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">The prior art includes an RF MEMS frequency tunable fractal antenna for the 0.1–6 GHz frequency range, and the actual integration of RF-MEMS on a self-similar Sierpinski gasket antenna to increase its number of resonant frequencies, extending its range to 5GHz, 14GHz and 30GHz, an RF MEMS radiation pattern reconfigurable spiral antenna for 6 and 10 GHz, an RF MEMS radiation pattern reconfigurable spiral antenna for the 6–7 GHz frequency band based on packaged Radant MEMS SPST-RMSW100 switches, an RF MEMS multiband Sierpinski fractal antenna, again with integrated RF MEMS switches, functioning at different bands from 2.4 to 18 GHz, and a 2-bit Ka-band RF MEMS frequency tunable slot antenna.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;"><strong><em>Filters</em></strong></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">RF bandpass filters are used to increase out-of-band rejection, if the antenna fails to provide sufficient selectivity. Out-of-band rejection eases the dynamic range requirement of low noise amplifier LNA and mixer in the light of interference. Off-chip RF bandpass filters based on lumped bulk acoustic wave (BAW), ceramic, surface acoustic wave (SAW), quartz crystal, and thin film bulk acoustic resonator (FBAR) resonators have superseded distributed RF bandpass filters based on transmission line resonators, printed on substrates with low loss tangent, or based on waveguide cavities. RF MEMS resonators offer the potential of on-chip integration of high-Q resonators and low-loss bandpass filters. The Q factor of RF MEMS resonators is in the order of 1000-1000.</div><div style="text-align: justify;"></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Tunable RF bandpass filters offer a significant size reduction over switched RF bandpass filter banks. They can be implemented using III-V semiconducting varactors, BST or PZT ferroelectric and RF MEMS switches, switched capacitors and varactors, and yttrium iron garnet (YIG) ferrites. RF MEMS technology offers the tunable filter designer a compelling trade-off between insertion loss, linearity, power consumption, power handling, size, and switching time.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;"><strong><em>Phase shifters</em></strong></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">RF MEMS phase shifters have enabled wide-angle passive electronically scanned arrays, such as lenses, reflect arrays, subarrays and switched beamforming networks, with high effective isotropically radiated power (EIRP), also referred to as the power-aperture product, and high Gr/T. EIRP is the product of the transmit gain, Gt, and the transmit power, Pt. Gr/T is the quotient of the receive gain and the antenna noise temperature. A high EIRP and Gr/T are a prerequisite for long-range detection. The EIRP and Gr/T are a function of the number of antenna elements per subarray and of the maximum scanning angle. The number of antenna elements per subarray should be chosen to optimize the EIRP or the EIRP x Gr/T product, as shown in Fig. 3 and Fig. 4.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;"></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhqBm7sllQFBFvUQNHFF2abIW0KIlm4nlE3hZa1ZB5-kNjMvuItObLPAcNVlEpo6-O7g_uQo2NqdXeEMd4T7cmuHHLqPLxjZsuuxbUIu8BqPFoZt_9fa-V3MOme75C0UpQgzSZyOqvZ0zRI/s1600/ii3.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" gu="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhqBm7sllQFBFvUQNHFF2abIW0KIlm4nlE3hZa1ZB5-kNjMvuItObLPAcNVlEpo6-O7g_uQo2NqdXeEMd4T7cmuHHLqPLxjZsuuxbUIu8BqPFoZt_9fa-V3MOme75C0UpQgzSZyOqvZ0zRI/s320/ii3.png" /></a></div><div class="separator" style="clear: both; text-align: center;"><br />
</div><div class="separator" style="clear: both; text-align: center;"><img border="0" gu="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEjTrfq8Xgs1VBpA21b8NpZXtFll2dDmHAEXMoeDhnHtOrDY13HLuwwXgZMSd4pqN6xdlSukxfwgbwruVAwIGhNgN9w4IlQjz9015PJyrY-CQop27qhZoCBTpzLVLuPymVk2KJ5_QKe63i7A/s320/ii4.png" /><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiBei2E8n4snXmr4u1LHLeGImeq0CB23IQe-T1dOA5EmaRhCne8dBnMPJX0FIr5zvxA-G98WTyIYFAlkieBQzzAtwnB9tQZYWuQ7U91T221dpvlypY6_A1-7bx9XjnH-qccHFR_UR_dRtyz/s1600/ii5.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" gu="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiBei2E8n4snXmr4u1LHLeGImeq0CB23IQe-T1dOA5EmaRhCne8dBnMPJX0FIr5zvxA-G98WTyIYFAlkieBQzzAtwnB9tQZYWuQ7U91T221dpvlypY6_A1-7bx9XjnH-qccHFR_UR_dRtyz/s320/ii5.png" /></a></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Passive subarrays based on RF MEMS phase shifters may be used to lower the amount of T/R modules in an active electronically scanned array. The statement is illustrated with examples in Fig. 3: assume a one-by-eight passive subarray is used for transmit as well as receive, with following characteristics: f = 38 GHz, Gr = Gt = 10 dBi, BW = 2 GHz, Pt = 4 W. The low loss (6.75 ps/dB) and good power handling (500 mW) of the RF MEMS phase shifters allow an EIRP of 40 W and a Gr/T of 0.036 1/K. The number of antenna elements per subarray should be chosen in order to optimize the EIRP or the EIRP x Gr/T product, as shown in Fig. 3 and Fig. 4. The radar range equation can be used to calculate the maximum range for which targets can be detected with 10 dB of SNR at the input of the receiver. </div><div style="text-align: justify;"></div><div style="text-align: justify;"><br />
</div><div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none; text-align: justify;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh97O83Ruc1kpBD_sXRc5lq7b-Jx9VORXgYnhhLPM_BagwjD5MH6xmM3Fgm5-7F9YNCFq6J0hd9ba_1Zsyy2052-HZg1l6AD-j3xTJu45gdODARuW5SQmIoYJF1H_2RSnWDzXAboIIbKbf_/s1600/ii9.png" imageanchor="1" style="clear: left; cssfloat: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" gu="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh97O83Ruc1kpBD_sXRc5lq7b-Jx9VORXgYnhhLPM_BagwjD5MH6xmM3Fgm5-7F9YNCFq6J0hd9ba_1Zsyy2052-HZg1l6AD-j3xTJu45gdODARuW5SQmIoYJF1H_2RSnWDzXAboIIbKbf_/s320/ii9.png" /></a>in which kB is the Boltzmann constant, λ is the free-space wavelength, and σ is the RCS of the target. Range values are tabulated in Table 1 for following targets: a sphere with a radius, a, of 10 cm (σ = π a2), a dihedral corner reflector with facet size, a, of 10 cm (σ = 12 a4/λ2), the rear of a car (σ = 20 m2) and for a contemporary non-evasive fighter jet (σ = 400 m2). A Ka-band hybrid ESA capable of detecting a car 100 m in front and engaging a fighter jet at 10 km can be realized using 2.5 and 422 passive subarrays (and T/R modules), respectively. </div><div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none; text-align: justify;"> </div><div style="text-align: justify;"></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj5NDbWqQZn8o5zx-SKmri1RmAhJ9CDzqemv5hftF9wmq4luR9QTcZ2S8pWKBEtZibvcfaK-X38WAMO6l-hN4AN3NS2X5sb-M5ttYrhG20EuOIaikEeQyar7mXE4EXstQFugfaSAujTJrTb/s1600/ii8.JPG" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" gu="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEj5NDbWqQZn8o5zx-SKmri1RmAhJ9CDzqemv5hftF9wmq4luR9QTcZ2S8pWKBEtZibvcfaK-X38WAMO6l-hN4AN3NS2X5sb-M5ttYrhG20EuOIaikEeQyar7mXE4EXstQFugfaSAujTJrTb/s320/ii8.JPG" /></a></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">The usage of true-time-delay TTD phase shifters instead of RF MEMS phase shifters allows ultra-wideband (UWB) radar waveforms with associated high range resolution, and avoids beam squinting or frequency scanning. TTD phase shifters are designed using the switched-line principle or the distributed loaded-line principle. Switched-line TTD phase shifters are superior to distributed loaded-line TTD phase shifters in terms of time delay per decibel noise figure (NF), especially at frequencies up to X-band, but are inherently digital and require low-loss and high-isolation SPNT switches. Distributed loaded-line TTD phase shifters, however, can be realized analogously or digitally, and in smaller form factors, which is important at the subarray level. Analog phase shifters are biased through a single bias line, whereas multibit digital phase shifters require a parallel bus along with complex routing schemes at the subarray level. In addition, usage of an analog bias voltage avoids large phase quantization errors, which deteriorate the EIRP and beam-pointing accuracy, and elevate the sidelobe level of an electronically scanned array. </div><div style="text-align: justify;"></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">The prior art in passive electronically scanned arrays, shown in Fig. 6, includes an X-band continuous transverse stub (CTS) array fed by a line source synthesized by sixteen 5-bit reflect-type RF MEMS phase shifters based on ohmic cantilever RF MEMS switches, an X-band 2-D lens consisting of parallel-plate waveguides and featuring 25,000 ohmic cantilever RF MEMS switches, and a W-band switched beamforming network based on an RF MEMS SP4T switch and a Rotman lens focal plane scanner.</div><div style="text-align: justify;"><br />
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</div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhhtG_8ixJOKzfQGTA5ukci0e4T-FnExOKPvOTOcfLeLJjMfV07TCxpzkQyrMTN0hxS1Tl5WpF0lINX7t6YaxUAGwPRxtH8oqYsWFp_yrbJSzUQSC7h5mYbp3_X2bQscQduU3xQGi0SQm1t/s1600/ii6.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" gu="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhhtG_8ixJOKzfQGTA5ukci0e4T-FnExOKPvOTOcfLeLJjMfV07TCxpzkQyrMTN0hxS1Tl5WpF0lINX7t6YaxUAGwPRxtH8oqYsWFp_yrbJSzUQSC7h5mYbp3_X2bQscQduU3xQGi0SQm1t/s320/ii6.png" /></a></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;"><strong><em>T/R modules</em></strong></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Within a T/R module, as shown in Fig. 7, RF MEMS limiters, tunable matching networks and TTD phase shifters can be used to protect the LNA, load-pull the power amplifier (PA) and time delay the RF signal, respectively. Whether RF MEMS T/R switches - i.e. single pole double throw (SPDT) switches, can be used depends on the duty cycle and the pulse repetition frequency (PRF) of the pulse-Doppler radar waveform. To date, RF MEMS duplexers can only be used in low PRF and medium PRF radar waveforms for long-range detection, which use pulse compression and therefore have a duty cycle in the order of microseconds.</div><br />
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</div><div class="separator" style="clear: both; text-align: justify;"><strong>Fuente:</strong> <a href="http://en.wikipedia.org/wiki/RF_MEMS">http://en.wikipedia.org/wiki/RF_MEMS</a></div><div class="separator" style="clear: both; text-align: justify;"><strong>Ver blogger original:</strong> <a href="http://nubia-anc.blogspot.com/">http://nubia-anc.blogspot.com/</a></div><div class="separator" style="clear: both; text-align: justify;"><strong>Materia: CRF</strong></div>Nubia A. Navarro C.http://www.blogger.com/profile/16124874914747829398noreply@blogger.com0tag:blogger.com,1999:blog-5677235594720330703.post-333266892606898732010-05-30T16:26:00.000-07:002010-05-30T16:27:46.629-07:00Oscilent SAW Filter Division<div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none; text-align: justify;"><br />
</div><div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none; text-align: justify;">Oscilent designs, manufactures, and promotes a full line of IF and RF SAW Filter products and solutions for wireless applications including GPS, PCS, PCN, CDMA, Wireless LAN, GMS, CATV, Bluetooth, keyless entry, and other datacom, handset, and broadband commercial and military/aerospace applications. Our capabilities span both low and high volume programs with particular focus on signal processing applications. In addition to our extensive offering of standard SAW Filter products, Oscilent has diverse Engineering experience spanning hundreds of custom designed SAW Filters, Bandpass Filters, Low Loss Filters and SAW based subsystems. Our custom/design/testing capabilities are unparalleled in our industry. </div><div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none; text-align: justify;"><br />
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</div><div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none; text-align: justify;"></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgj_U_EY_zpL9U2I386SLB1GlKiU1TvE3jz1dwkkPO8eXkzGSWuTB0oiu0Zx7n30cct2mkwxujBEobq6g7QiLhFHZp-4UC3GoEKOgEA8Ia18sQwUthm3FM8gHPvb_F1_MHFfy6vORm4u-a2/s1600/i3.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" gu="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgj_U_EY_zpL9U2I386SLB1GlKiU1TvE3jz1dwkkPO8eXkzGSWuTB0oiu0Zx7n30cct2mkwxujBEobq6g7QiLhFHZp-4UC3GoEKOgEA8Ia18sQwUthm3FM8gHPvb_F1_MHFfy6vORm4u-a2/s320/i3.jpg" /></a><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi4ZVCsR48ZSAo8Qnkf641L4KUb9mAxkUFc0mzDWH5_In8fzkxz4sgit4XEnkv7m9mZ9nQTplpxL1F38JWK07DMDej5gbMLrcLUUPnfi1K5yqNB4m9zPLgKTcO6m79Xq4BC2zYyEkhdX2Ri/s1600/i4.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" gu="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEi4ZVCsR48ZSAo8Qnkf641L4KUb9mAxkUFc0mzDWH5_In8fzkxz4sgit4XEnkv7m9mZ9nQTplpxL1F38JWK07DMDej5gbMLrcLUUPnfi1K5yqNB4m9zPLgKTcO6m79Xq4BC2zYyEkhdX2Ri/s320/i4.jpg" /></a></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiVrnY_hV57hMLcTuXZOlt4GKhgrs7oEvytAuvkuyT24phYZucC_rgD_g93HBCxByH-TiALRPDFPktRmW3RTi641B1tK0_9N1HBonB00OoANhKoel-G89cJjem2Rmiy2_QiuqZJe7p9oev-/s1600/i5.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" gu="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEiVrnY_hV57hMLcTuXZOlt4GKhgrs7oEvytAuvkuyT24phYZucC_rgD_g93HBCxByH-TiALRPDFPktRmW3RTi641B1tK0_9N1HBonB00OoANhKoel-G89cJjem2Rmiy2_QiuqZJe7p9oev-/s320/i5.jpg" /></a><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhnp7UQgeyxHt1xz6ewTSTC1sxgihNYWc5hgWlIo1nzzFWAH7NSNRFB8VNcN0l-Cl58sZks1Td_oghi3HiMBC9dCS70psFkR5cjiGJ85CaY0eT15vn6t53qjLwnSSeLBuE2j8Qyh34WXcxw/s1600/i6.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" gu="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhnp7UQgeyxHt1xz6ewTSTC1sxgihNYWc5hgWlIo1nzzFWAH7NSNRFB8VNcN0l-Cl58sZks1Td_oghi3HiMBC9dCS70psFkR5cjiGJ85CaY0eT15vn6t53qjLwnSSeLBuE2j8Qyh34WXcxw/s320/i6.jpg" /></a></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;"><strong><em>SAW Filter General Information</em></strong> </div><div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none; text-align: justify;"><br />
</div><div style="text-align: justify;">Advantages of SAW Filter technology include compact packages, low shape factors, superior linear phase characteristics, rejection qualities, and the relatively stable performance over temperatures. Many other advantages are derived from the physical structure of SAW Filters which allow for extremely robust and reliable designs that remain stable in the field/application. Additionally, the inherent design and wafer processing techniques of Saw Filters provide for a repeatable device in both low and high volume production. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Surface Accoustic Wave (SAW) fundamentals provide for a piezoelectric material that converts an incoming electromagnetic signal into an acoustic signal, and vice versa. In its most basic form, a SAW filter consists of a polished piezoelectric substrate with a deposit of two transducers with interdigital arrays of thin electrodes. The electrodes making up the arrays alternate polarities so that when an RF signal voltage is applied across them, a surface wave is then generated. In designing a SAW Filter, the overall frequency response characteristics are determined by deriving two impulse responses for the two transducers whose transforms are added together in dB. The surface of a piezoelectric substrate is then etched with the two impulse responses. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;"><strong><em>Selecting an Oscilent SAW Filter</em></strong> </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Generally, a SAW Filter manufacturer will offer their most popular devices as standards creating a reference for Engineers to design from. Typically, and especially true in the RF SAW Filter category, a standard device is available for most common applications. However, for applications requiring parameters that are not currently considered industry standards, Oscilent is uniquely equipped to offer design and development services at comparatively lower costs than our competitors. In this case, the following information is required to effectively design a SAW Filter: </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;"><strong><em>The following link can be used to print and fax your SAW Filter requirements to our Engineering Staff:</em></strong> </div><div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none;"><br />
</div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEibFRjUwzfwLd3l5vzH3UlMijVsCFuxlqfL_HRTmAwSH035euqR5CE7GDHGkw8Shr18X-uKyiTRi5C9vYVh09_UtAcaAM4gFHME-H-sCY21ggi2WONqO7p1aYEZgian6FaA0DfFyYyMRVGu/s1600/i7.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" gu="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEibFRjUwzfwLd3l5vzH3UlMijVsCFuxlqfL_HRTmAwSH035euqR5CE7GDHGkw8Shr18X-uKyiTRi5C9vYVh09_UtAcaAM4gFHME-H-sCY21ggi2WONqO7p1aYEZgian6FaA0DfFyYyMRVGu/s320/i7.jpg" /></a></div><div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none;"><br />
<strong>a. Center Frequency (Fo)</strong> </div><div style="text-align: justify;"></div><div style="text-align: justify;"><br />
</div><div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none; text-align: justify;"><strong>b. Passband Width (Bp)</strong> </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Simply stated, the Passband Width will pass a signal occupying a specific frequency band, and reject others falling outside the band. From a SAW Filter design perspective, the first parameter to consider is the Fractional Bandwidth (Bp/Fo) because of the influence on the substrate material to be used in the design. The substrate material influences many parameters, most importantly the Temperature Stability specifications. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;"><strong>c. Amplitude Ripple over Passband Width (AR)</strong> </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">The Amplitude Ripple is a measure (dB) of the variation, or differential value, of attenuation in the passband of a filter, typically a SAW Filter will be specified as having a Typical and Maximum allowable value. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;"><strong>d. Group Delay Variation over Passband Width (GDR)</strong> </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">From a mathematical perspective measured in time, the Group Delay of a SAW Filter is the first differential value of time for phase frequency of phase changing (variation) in pass band. Otherwise, we can reference the Group Delay as the slope of the Phase vs. Frequency Curve. In simple terms, the Group Delay represents the time it takes for the signal to pass through the SAW Filter. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;"><strong>e. Transition Bandwidth (Bt)</strong> </div><div style="text-align: justify;"><br />
</div><div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none; text-align: justify;">Otherwise referred to as Skirts, the area between the Stop Band and the Passband found on both sides of the Passband. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;"><strong>f. Rejection (REJ.)</strong> </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">All ranges of the SAW Filter not including the Passband. The Rejection can also be referred to as the Rejection Range, or Stop Band. We can refer to this as the range in which the Relative Attenuation is larger than the specified Rejection side. With proper material selection and design, Rejection of 50dB, or greater, is possible within a wide selection of fractional bandwidths and shape factors. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;"><strong>g. Insertion Loss (IL)</strong> </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Advances in SAW Filter design techniques routinely allow for a design incorporating a specification of under 10dB Insertion Loss, however, the minimum attainable Insertion Loss is generally influenced by the Fractional Bandwidth and the influences of this ratio on the applicable substrate material. The Insertion Loss value will generally increase when approaching the fractional bandwidth limit of a substrate material. For instance, a Fractional Bandwidth value of 8% will generally produce lower Insertion Loss than a Fractional Bandwidth value of 30% using the same substrate material. </div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;"><strong>h. Package</strong> </div><div style="text-align: justify;"><br />
</div><div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none; text-align: justify;">Factors affecting the size of the package used in SAW Filter design include parameters associated with Center Frequency, Bandwidth, and Shape Factor, among other minor considerations. For instance, lower Frequencies require larger substrate, thereby increasing the size of the packages available to the designer. Consequently, an equally important challenge of package size reduction is always considered by Oscilent Design Engineers in an attempt to meet the desired parameters in the smallest package possible. In selecting a package, we recommend stating general preferences. Without this input, Oscilent will design using the most cost effective approach balancing parameter requirements with cost and manufacturability. </div><div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none; text-align: justify;"><br />
</div><div style="text-align: justify;"><strong>Fuente:</strong> <a href="http://www.oscilent.com/catalog/Category/saw_filter.htm">http://www.oscilent.com/catalog/Category/saw_filter.htm</a></div><div style="text-align: justify;"><strong>Ver blogger original:</strong> <a href="http://nubia-anc.blogspot.com/">http://nubia-anc.blogspot.com/</a></div><div style="text-align: justify;"><strong>Materia: CRF</strong></div>Nubia A. Navarro C.http://www.blogger.com/profile/16124874914747829398noreply@blogger.com0tag:blogger.com,1999:blog-5677235594720330703.post-25532592171310325932010-05-30T16:07:00.000-07:002010-05-30T16:09:11.625-07:00Surface Acoustic Wave<div style="text-align: justify;"><br />
A surface acoustic wave (SAW) is an acoustic wave traveling along the surface of a material exhibiting elasticity, with an amplitude that typically decays exponentially with depth into the substrate.</div><div class="separator" style="clear: both; text-align: center;"><br />
</div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEioLs4xPp6FWbwOXf-mztJ5NpoPP0wvgWTpfRWAUW2b_IfLVecQNIredVYEHU57lDBJV2XLhhauoU7vlTKOP0B6_hS2ml9wm5kk2vcXRibr14U0Xr9e4AWMU3L8dylDiFG5XMQJ9bq_3O8m/s1600/i1.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"></a><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhdVMhTkrwx5vMoTfHsB1VEUuh-Jsrwob4V30yFzVhCBPCgM-283i4MlKEz9Mdmw_o2By-RRsnjUNL5pMrohzajgQM-Md5uCK-zcb3Zpl5nufz6jzsyiccJtJjDwAqa6ViZtMZHYDX8OCiC/s1600/i1.jpg" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" gu="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEhdVMhTkrwx5vMoTfHsB1VEUuh-Jsrwob4V30yFzVhCBPCgM-283i4MlKEz9Mdmw_o2By-RRsnjUNL5pMrohzajgQM-Md5uCK-zcb3Zpl5nufz6jzsyiccJtJjDwAqa6ViZtMZHYDX8OCiC/s320/i1.jpg" /></a></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;"><em><strong><span style="font-size: large;">Discovery</span></strong></em></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">SAWs were first explained in 1885 by Lord Rayleigh, who described the surface acoustic mode of propagation and predicted its properties in his classic paper.[1] Named after their discoverer, Rayleigh waves have a longitudinal and a vertical shear component that can couple with any media in contact with the surface. This coupling strongly affects the amplitude and velocity of the wave, allowing SAW sensors to directly sense mass and mechanical properties.</div><div style="text-align: justify;"></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;"><strong><em><span style="font-size: large;">Application in electronic components</span></em></strong></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">This kind of wave is commonly used in devices called SAW devices in electronic circuits. SAW devices are used as filters, oscillators and transformers, devices that are based on the transduction of acoustic waves. The transduction from electric energy to mechanical energy (in the form of SAWs) is accomplished by the use of piezoelectric materials.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;"></div><div class="separator" style="clear: both; text-align: center;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgqE8IctiCkNDSrlTR4MmVOpnAaZHOIfxCKfg2GVIH6zpAdM677aIcCE4fIkyOTBVQWKz16R8iUg1JFUT9rPlA2rfB0-iqACUBoBnergC8_piFImkpUg8vi8ySvSplDDu04DTnjVWoZTccc/s1600/i2.png" imageanchor="1" style="margin-left: 1em; margin-right: 1em;"><img border="0" gu="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEgqE8IctiCkNDSrlTR4MmVOpnAaZHOIfxCKfg2GVIH6zpAdM677aIcCE4fIkyOTBVQWKz16R8iUg1JFUT9rPlA2rfB0-iqACUBoBnergC8_piFImkpUg8vi8ySvSplDDu04DTnjVWoZTccc/s320/i2.png" /></a></div><div class="separator" style="clear: both; text-align: center;"><br />
</div><div style="text-align: justify;">Electronic devices employing SAWs normally use one or more interdigital transducers (IDTs) to convert acoustic waves to electrical signals and vice versa by exploiting the piezoelectric effect of certain materials (quartz, lithium niobate, lithium tantalate, lanthanum gallium silicate, etc.).[2] These devices are fabricated by photolithography, the process used in the manufacture of silicon integrated circuits.</div><div style="text-align: justify;"></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">SAW filters are now used in mobile telephones, and provide significant advantages in performance, cost, and size over other filter technologies such as quartz crystals (based on bulk waves), LC filters, and waveguide filters.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Much research has been done in the last 20 years in the area of surface acoustic wave sensors.[3] Sensor applications include all areas of sensing (such as chemical, optical, thermal, pressure, acceleration, torque and biological). SAW sensors have seen relatively modest commercial success to date, but are commonly commercially available for some applications such as touchscreen displays.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;"><strong><em><span style="font-size: large;">SAW in geophysics</span></em></strong></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">In seismology surface acoustic waves travelling along the Earth's surface play an important role, since they can be the most destructive type of seismic wave produced by earthquakes.</div><div style="text-align: justify;"><br />
<strong><em><span style="font-size: large;">SAW in microfluidics</span></em></strong></div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">In recent years, attention has been drawn to using SAWs to drive microfluidic actuation and a variety of processes. Owing to the mismatch of sound velocities in the SAW substrate and fluid, SAWs can be efficiently transferred into the fluid, to create significant inertial force and fluid velocities. This mechanism can be exploited to drive fluid actions such as pumping, mixing, jetting, as well as others.</div><div style="text-align: justify;"><br />
</div><strong>Fuente:</strong> <a href="http://en.wikipedia.org/wiki/Surface_acoustic_wave">http://en.wikipedia.org/wiki/Surface_acoustic_wave</a><br />
<strong>Ver blogger original:</strong> <a href="http://nubia-anc.blogspot.com/">http://nubia-anc.blogspot.com/</a><br />
<strong>Materia: CRF</strong>Nubia A. Navarro C.http://www.blogger.com/profile/16124874914747829398noreply@blogger.com0tag:blogger.com,1999:blog-5677235594720330703.post-50674308871557996312010-05-28T18:54:00.000-07:002010-05-30T16:08:36.963-07:00Tecnología de Microondas<div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none; text-align: justify;"></div><div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none; text-align: justify;"><br />
</div><div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none; text-align: justify;"><div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none;"><a href="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh6Y7XkAlWmg6W4dVCxyiZEU1a_GLO49OLImHp58BJUfh8oZEbX6BmGsE8FlobLOy11OWl38SSoixErV6ygRYHEYNtAbntGiwUNc8A1U5s8bnD5GDlQh2mBVMCehP7UPM894YAtvKnxRn9B/s1600/10.jpg" imageanchor="1" style="clear: left; cssfloat: left; float: left; margin-bottom: 1em; margin-right: 1em;"><img border="0" gu="true" src="https://blogger.googleusercontent.com/img/b/R29vZ2xl/AVvXsEh6Y7XkAlWmg6W4dVCxyiZEU1a_GLO49OLImHp58BJUfh8oZEbX6BmGsE8FlobLOy11OWl38SSoixErV6ygRYHEYNtAbntGiwUNc8A1U5s8bnD5GDlQh2mBVMCehP7UPM894YAtvKnxRn9B/s320/10.jpg" /></a></div></div><div style="border-bottom: medium none; border-left: medium none; border-right: medium none; border-top: medium none; text-align: justify;"><br />
<br />
Departamento de Microondas<br />
<br />
Director del Departamento<br />
Albert Gort, Ingeniero Eléctrico<br />
<br />
<br />
<br />
<strong><em>“Nuestro interés principal es educar a la gente de todo el mundo con respecto a los peligros de la tecnología de microondas y apoyarlos en promover una vida saludable sin microondas. La peligrosa tecnología anti-natural de microondas actual, que es aplicada en diferentes áreas de la vida, debe ser prohibida alrededor del mundo y reemplazada por una tecnología que esté de acuerdo con la Naturaleza y que por lo tanto no cause daño al hombre o la Naturaleza."</em></strong></div><br />
<div style="text-align: left;"><strong><span style="font-size: large;"><em>El Problema</em></span></strong></div><br />
<div style="text-align: justify;">La tecnología de microondas, que es usada para la telecomunicación móvil, hornos de microondas, teléfonos inalámbricos, teléfonos de bebés con un estándar DECT, tecnología de armas, manipulación del clima y en cualquier sistema nuevo, se está convirtiendo en la amenaza más peligrosa para toda vida que ha sido creada por el hombre. Nunca antes el hombre y la naturaleza han sido expuestos a tan extensivo y violento poder destructivo.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">El potencial de daño de esta radiación tecnológica anti-natural es más alto y más dramático de lo que aún los oponentes de la telecomunicación móvil generalmente son conscientes. Porque no solamente se trata del umbral de valores o de la cantidad de radiación que amenaza al hombre y la naturaleza, sino también es- primero y más importante- la calidad de esta radiación anti- natural.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">La ley de Paracelso dice, que es la cantidad lo que determina si una sustancia es un veneno o no. Sin embargo, ésto solo puede ser aplicado a sustancias naturales. Para sustancias sintéticas o técnicamente producidas y radiación se aplica la ley de Petkau, la cual dice que una pequeña dosis durante un largo período de tiempo es más dañina que una dosis alta en un período de tiempo corto.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Todo sistema viviente ha sido creado por impulsos electromagnéticos naturales. Todos ellos son continuos y funcionan debido a estos procesos electromagnéticos naturales. Esta es la vida. Minerales, plantas, animales y personas son 'sistemas electromagnéticos', originados dentro de un ser por una mente creativa inteligente. Todo obedece al orden divino. El universo entero, constituido de las más pequeñas partículas de luz, vibra en varias frecuencias de acuerdo a su conciencia directa subyacente. Todo es vibración y conciencia.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">La radiación de microondas técnica anti-natural interfiere con todos estos procesos sensibles, que suceden en todas partes en la naturaleza y en nuestros cuerpos. La consecuencia inevitable será la enfermedad y el deterioro. Es una cuestión de tiempo hasta que las consecuencias se hagan visibles. Por eso La Fundación Mundial para las Ciencias Naturales ha estado alertando durante años con respecto a los efectos nocivos de esta radiación anti-natural y es el por qué nosotros hemos estado promoviendo vehementemente una vida saludable sin microondas. Y con microondas nosotros nos referimos a la gama completa de aplicaciones de esta radiación anti-natural, incluyendo ultrasonido, ondas de radio y televisión, etc.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">Nuestros materiales de información, especialmente nuestra película "Para una Vida Sana sin Microondas", están diseñados para educar al público, para informar y prevenirlos de los peligros de esta tecnología y apoyarlos en su esfuerzo para defenderse ellos mismos. La Fundación Mundial para las Ciencias Naturales es una organización científica Franciscana y toma siempre enfoques naturales y espirituales en consideración en su intento de una solución. Con nuestra visión holística de este problema nosotros demandamos el desarrollo inmediato de tecnologías alternativas que estén de acuerdo con el Orden Divino y así no causen ningún daño sobre el hombre o la naturaleza.</div><div style="text-align: justify;"><br />
</div><div style="text-align: justify;">El derecho a la vida y a la inviolabilidad física son derechos básicos del hombre. Por lo tanto están sobre todas las otras leyes. Hoy en día estos derechos básicos son violados masivamente por el uso actual de la tecnología de microondas. Debido a su amor por la humanidad y la naturaleza La Fundación Mundial para las Ciencias Naturales promueve una vida saludable sin microondas. Nosotros le pedimos desde el fondo de nuestros corazones apoyarnos en este esfuerzo. Nuestro material de información puede ser pedido en nuestro Comercio en línea. </div><div style="text-align: justify;"><br />
</div><strong>Fuente:</strong> <a href="http://www.naturalscience.org/index.php?id=24&L=2">http://www.naturalscience.org/index.php?id=24&L=2</a> <br />
<strong>Ver blogger original:</strong> <a href="http://nubia-anc.blogspot.com/">http://nubia-anc.blogspot.com/</a><br />
<strong>Materia: CRF</strong>Nubia A. Navarro C.http://www.blogger.com/profile/16124874914747829398noreply@blogger.com0