Advanced characterization of a W-band phase shifter based on liquid crystals and MEMS technology

Fritzsch, Carsten; Giacomozzi, F.; Karabey, Onur Hamza; Bildik, Saygin; Colpo, S.; Jakoby, Rolf

doi:10.1017/s1759078712000311

Cited by 17 publications

(10 citation statements)

References 17 publications

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“…11 and 12. As summarized in Table II, our design presents a tangible improvement in the overall performance when compared with that of a recent work [5].…”

Section: B Connector Compensation and Whole Device Performancementioning

confidence: 86%

Design of liquid crystal based coplanar waveguide tunable phase shifter with no floating electrodes for 60–90 GHz applications

Chu

2016

2016 46th European Microwave Conference (EuMC)

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A continuously tunable millimeter wave (mmwave) phase shifter for 60-90 GHz applications was proposed using a coplanar waveguide (CPW) structure without the use of a floating electrode (FE). In contrast to conventional CPW-FE structures, the proposed FE-free CPW device can be modulated by the nematic liquid crystal (LC) materials confined in two symmetric feeding channels. The nearly true-TEM nature of this CPW design enables wideband and low-loss operations, particularly in high frequencies up to 90 GHz. In order to optimize between high tunability and low loss, the aspect ratio of the CPW structure was optimized to maximize the defined Figure-of-Merit (FoM). By taking into account different loss mechanisms in the designed structure and the effect of LC orientations, the driving-voltage dependent impedance matching was examined to minimize the return and insertion losses. As an example, the design of a phase shifter aimed to operate at 79 GHz with low bias voltages (0-10 V) is presented, showing a wide phase shift range of 0-408° and a low insertion loss from-6.15dB to-4.56dB. The corresponding FoM is 66.3°/dB, which is expected to outperform over other LC-based phase shifters as reported within the targeted frequency range of 60-90 GHz.

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“…11 and 12. As summarized in Table II, our design presents a tangible improvement in the overall performance when compared with that of a recent work [5].…”

Section: B Connector Compensation and Whole Device Performancementioning

confidence: 86%

Design of liquid crystal based coplanar waveguide tunable phase shifter with no floating electrodes for 60–90 GHz applications

Chu

2016

2016 46th European Microwave Conference (EuMC)

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“…Investigations of the transient behavior of this loaded-line phase shifter in MEMS technology is shown in Figure 29, where the rise and decay of the measured differential phase shift with respect to its maximum 8 for hLC in between 4.5 and 5 µm. This concept was proposed for the first time in [267,268] and realized in the W-band. The CPW line was processed on a 300 µm thick fused silica substrate, where the ground planes are made of a 5 µm thick gold layer, while the signal line is made of a 600 nm thick multi-metal Ti-TiN-Al-Ti-TiN layer with a 150 nm thick gold layer on top, creating a floating metal bridge.…”

Section: Bottom Substratementioning

confidence: 99%

Microwave Liquid Crystal Enabling Technology for Electronically Steerable Antennas in SATCOM and 5G Millimeter-Wave Systems

Jakoby

Gaebler²,

Weickhmann³

2020

Crystals

Self Cite

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Future satellite platforms and 5G millimeter wave systems require Electronically Steerable Antennas (ESAs), which can be enabled by Microwave Liquid Crystal (MLC) technology. This paper reviews some fundamentals and the progress of microwave LCs concerning its performance metric, and it also reviews the MLC technology to deploy phase shifters in different topologies, starting from well-known toward innovative concepts with the newest results. Two of these phase shifter topologies are dedicated for implementation in array antennas: (1) wideband, high-performance metallic waveguide phase shifters to plug into a waveguide horn array for a relay satellite in geostationary orbit to track low Earth orbit satellites with maximum phase change rates of 5.1°/s to 45.4°/s, depending on the applied voltages, and (2) low-profile planar delay-line phase shifter stacks with very thin integrated MLC varactors for fast tuning, which are assembled into a multi-stack, flat-panel, beam-steering phased array, being able to scan the beam from −60° to +60° in about 10 ms. The loaded-line phase shifters have an insertion loss of about 3 dB at 30 GHz for a 400° differential phase shift and a figure-of-merit (FoM) > 120°/dB over a bandwidth of about 2.5 GHz. The critical switch-off response time to change the orientation of the microwave LCs from parallel to perpendicular with respect to the RF field (worst case), which corresponds to the time for 90 to 10% decay in the differential phase shift, is in the range of 30 ms for a LC layer height of about 4 µm. These MLC phase shifter stacks are fabricated in a standard Liquid Crystal Display (LCD) process for manufacturing low-cost large-scale ESAs, featuring single- and multiple-beam steering with very low power consumption, high linearity, and high power-handling capability. With a modular concept and hybrid analog/digital architecture, these smart antennas are flexible in size to meet the specific requirements for operating in satellite ground and user terminals, but also in 5G mm-wave systems.

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“…, and the effective loss tangent, [28], of the delay section were also computed using (6) in conjunction with the measurement data for the two sets of the thru and line in Fig. 3 and they are shown in Fig.…”

Section: S-parameters Of Transitionsmentioning

confidence: 99%

“…where is defined by (6). In (9), corresponding to represents the wave phase constant in the LC layer.…”

Section: A Extraction Techniquementioning

confidence: 99%

Microstrip Device for Broadband (15–65 GHz) Measurement of Dielectric Properties of Nematic Liquid Crystals

Deo

Mirshekar‐Syahkal

Seddon

et al. 2015

IEEE Trans. Microwave Theory Techn.

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The essential dielectric properties, the basic alignment techniques, and the common measurement methods of the nematic liquid crystal (LC) at RF are briefly reviewed. A new device for the broadband measurement of the dielectric constants and loss tangents of nematic LCs at microwave and millimeter-wave frequencies is presented. This device whose specification and fabrication are outlined is essentially a two dielectric layer microstrip structure with coplanar-waveguide terminals, which is easy to fabricate. Compared to previous structures, the proposed device is extremely broadband with 15-65-GHz bandwidth, benefits from a solid exposed ground plane for easy temperature test, and operates under bias voltage. The technique for the extraction of the dielectric parameters of the nematic LC analyzed by this device is explained and the sources imposing the frequency limits on the device performance are identified. Two different nematic LCs, MDA-00-3506 and GT3-23001, are characterized and the results are shown to compare well with those available in the literature. In the comparisons, the maximum difference found for the dielectric constants for MDA-00-3506 is 5% and for GT3-23001 is 5.3%.

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Advanced characterization of a W-band phase shifter based on liquid crystals and MEMS technology

Cited by 17 publications

References 17 publications

Design of liquid crystal based coplanar waveguide tunable phase shifter with no floating electrodes for 60–90 GHz applications

Design of liquid crystal based coplanar waveguide tunable phase shifter with no floating electrodes for 60–90 GHz applications

Microwave Liquid Crystal Enabling Technology for Electronically Steerable Antennas in SATCOM and 5G Millimeter-Wave Systems

Microstrip Device for Broadband (15–65 GHz) Measurement of Dielectric Properties of Nematic Liquid Crystals

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