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9-2016

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RF & Wireless Figure 11:

RF & Wireless Figure 11: Currents and radiation pattern shown in AXIEM simulation, as well as good agreement with simulation and measurement results Figure 12: The fabricated UWB antenna prototype width and 10” height, replacing the 10” wide x 7” high initial version. The original frequency band definition was kept at 300 MHz to 1 GHz and the antenna types were pre-selected as before. The taller antenna form factor worked much better, though the desired outcome was still not achieved. Exploring the Low-Frequency Limit With the low end VSWR results still out of spec, AntSyn was used to explore what was possible at the lower end of the frequency range. The designer knew that AntSyn could design an antenna at a single frequency much faster than over a wide band and that if a match to a single frequency cannot be obtained for a given form factor, it is unlikely that a wide band antenna can. So, the target frequency was changed to a single, lower value (200 MHz) while maintaining the 7” wide x 10” tall form factor (Figure 3). While the VSWR result at 200 MHz for the asymmetric genetic monopole was acceptable, its appearance suggested that it would be unlikely to achieve broadband performance while maintaining the low desired frequency response. The other antennas showed poor performance at 200 MHz, illustrating the difficultly of achieving this frequency within this size limit. This experiment established that the 200 MHz low end would be difficult to achieve with a broadband antenna. To fully understand the impact of size on performance, the form factor constraint was also relaxed to investigate structures within a 12” height limit. While two antenna types (Figure 4) showed improvement in the VSWR performance, the increased form factor was undesirable to the overall system requirements. It remained to be seen if the additional performance would be worth the expansion in the form factor. Zeroing in on the Final Specs In this phase, AntSyn was used to set the final values for the frequency and dimensional limits. AntSyn was used to see if the upper frequency range could be expanded to 2.5 GHz, as a higher frequency limit is usually much easier to achieve than extending the lower frequency range. Results showed that doing so was indeed relatively easy. The form factor width was also expanded to 7.5” after re-evaluating the maximum limits of the form factor for the application. However, results showed that expanding the height to 12” did not sufficiently improve the lower frequency performance to warrant the extra size. Various low frequency values (250, 300, 325, 350 MHz) were attempted, with 325 MHz determined as the final low-frequency spec to meet (Figures 5 and 6). Finalizing the Design Now that the specifications were finalized, the AntSyn spec sheet was set to high RQ in order to create the design best able to meet those specifications. Monopoles and dipoles were explored. While the results were good for the monopoles, the antenna layout was not ideal for the application, so dipoles were examined more thoroughly. The designer explored the UWB dipole type antenna with spec sheet settings as shown in Figure 7. The results are shown in Figure 8. Since the results were nearly symmetric for the asymmetric dipole, the genetic dipole (which has enforced symmetry) was optimized further. Figure 9 is the spec sheet for this trial and Figure 10 reveals the best result. This genetic dipole antenna was selected for fabrication because the VSWR was lower for 1.1– 2.1 GHz and the areas of higher VSWR were determined not to be an issue. In addition, the form factor was determined to be better for the application. AXIEM EM Verification After achieving satisfactory results, the antenna data was transferred to NI AWR Design Environment in planar DXF format for verification using AXIEM 3D planar EM simulator (Figure 11). There were several ways to feed the antenna and for this prototype an edge SubMiniature version A (SMA) connector and a microstrip feed were chosen. The radiators were placed on different sides of a 20 mil Rogers 4003C substrate. The simulations in AXIEM confirmed that the feed line, radiator arrangement, and substrate did not significantly affect antenna performance. Prototype and Measurement In order to fabricate the antenna, the AXIEM layout was exported in Gerber format and a prototype manufactured. The prototype was measured with a 1-port vector network analyzer (VNA) (Figure 12). The measured VSWR

RF & Wireless News Skyworks Expands Antenna Tuning Portfolio Skyworks Solutions Inc. expanded its best-in-class antenna tuning product portfolio with the addition of several new high performance solutions. Skyworks’ latest antenna tuning offerings address the design challenges mobile device manufacturers face as smartphones become thinner, leverage revolutionary case materials and integrate more cellular bands. By optimizing radiated efficiency, Skyworks’ antenna aperture tuners enable higher data throughput and smaller footprints, minimizing dropped calls and improving the consumer experience. Skyworks’ new antenna tuning switches provide low R on for higher efficiency, transfer more power to the antenna, offer low C off to deliver accurate and consistent tuning results, enable high V peak for improved radiated spurious emission (RSE) performance and integrate GPIO-control for ease of use. To simplify the design process and accelerate time-to-market, Skyworks assists with antenna modeling, data simulation, design and layout optimization, and onsite support to help customers leverage these advanced antenna tuning products into their platforms. These products are shipped in a RoHS compliant plastic package with compact 10 pin 1.1 x 1.5 x 0.5 mm quad-flat noleads (QFN). The common footprint of these devices allows customers to utilize one layout across multiple designs. These new devices are available in the following configurations: SP2T – SKY19243-686LF, SP3T – SKY19244- 686LF, SP4T – SKY19245-686LF. ■ Skyworks Solutions Inc. www.skyworksinc.com Antennas SWA Body Worn Antennas RFMW, Ltd. announced design and sales support for two new body worn antennas from Southwest Antennas. Model 1065-028 is a right-hand, circularly polarized (RHCP) antenna while model 1065-029 offers lefthand polarization (LHCP). Developed to offer a high performance, rugged antenna option, the antenna radome housing is resistant to damage from drops, being stepped or jumped on, and other potential abuse. Both 1065-028 and 1065-029 antennas are designed for use with handheld or body worn MIMO/MANET or SISO radio systems operating from 2100 to 2500 MHz. Circular polarization offers performance enhancements in multi-antenna radio configurations, crowded RF/non line-of-sight scenarios, and improved performance in adverse weather conditions providing greater radio range for law enforcement, military or civilian applications. Free-space gain is specified at 4.5 dBic. Measuring only 2.2 x 2.2 x 0.51 inches and weighing 1.3 ounces, the 1065- 028 and 1065-029 are lighter, smaller and more rugged than similar antennas currently on the market and are easily secured into pouches, vests and MOLLE gear. ■ RFMW, Ltd. info@rfmw.com www.rfmw.com Ultra-low profile antenna for 3G, LTE and MIMO Antenova M2M introduced Similis, a new, ultra-low profile antenna for 3G, LTE and MIMO. The Similis antenna measures just 40 x 10 x 1.6 mm, making it literally half the height of the popular Lucida which Antenova introduced last year. This exceptionally slim antenna will definitely be among the very thinnest embedded antennas on the market. Antenova has designed the Similis antenna for low profile M2M and IoT applications where space is tight and its size will be a real advantage – in particular, it offers a lower profile than leading wireless cellular modules which are usually more than 2 mm in height. This new antenna is suitable for Femto/base stations, portable devices, remote monitoring, smart meters, network devices and wearable electronics. Similis is designed to be integrated within a device, so the considerations of its placement on the PCB and the antenna’s performance within the device have all been addressed at the design stage, making this new antenna easy to integrate into a design. ■ Antenova M2M sales@antenova-m2m.com www.antenova-m2m.com 18 GHz SMA 4-Hole Flange Connector with Solder Cup RFMW, Ltd. announced design and sales support for the Delta Electronics Manufacturing 1313000G051-000, an 18 GHz SMA female, four-hole, flange mount connector with solder cup. Produced for commercial, industrial, and military applications where a quality SMA interconnect is required, the 1313000G051-000 connector body is stainless steel with gold plating per MIL-G-45204 and houses a Teflon dielectric. The center contact is gold plated. Applications for the 1313000G051-000 SMA include instrumentation, wireless infrastructure, ground based satellite and radar, industrial radios and test and measurement equipment. The flange measures 0.5 inches square. ■ RFMW, Ltd. info@rfmw.com www.rfmw.com hf-praxis 9/2016 33

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