Microwave High-Speed Liquid Crystal Devices Using CPW with Floating Electrode

Utsumi, Yozo; Kamei, Takeshi; Maeda, Takehiko; Dinh, Nguyen Quoc

doi:10.1080/15421400701739121

Cited by 17 publications

(10 citation statements)

References 4 publications

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“…However, limited by the current status of LC mm-wave technology in which most of the LC-based devices have been designed for <40 GHz, LC-based tunable phase shifters and other phase components are not well established in the frequency regime of 60-90 GHz. LC-based coplanar waveguide (CPW) variable phase shifters reported [2] [3] were based on tuning in the interlayer between coplanar electrodes and the floating electrode (FE) on top. This has an advantage of relatively fast electrically tuning speed due to the thin LC layer required.…”

Section: Introductionmentioning

confidence: 99%

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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Section: Introductionmentioning

confidence: 99%

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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“…For this reason, intensive research has focused on applications of LC in GHz. [6][7][8][9][10][11][12]. This work includes the assessment of selected nematic liquid crystals in terms of dielectric permittivity modulation in 0.01-6 GHz range.…”

Section: Introductionmentioning

confidence: 99%

Measurement of Dielectric Anisotropy of Some Liquid Crystals for Microwave Applications

Trushkevych

Collings

et al. 2009

Molecular Crystals and Liquid Crystals

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“…To solve these problems, we propose a coplanar waveguide with a floating electrode (CPW-FE) to achieve a high-speed device. [7][8][9][10] The aim of this study is to obtain the design data of an efficient nematic-liquid-crystal-loaded phase shifter with a CPW-FE. We first fabricate a liquid-crystal-loaded CPW-FE phase shifter with a straight-line structure and investigate the tendency of its response time and phase characteristics by performing microwave measurements while varying structural parameters.…”

Section: Introductionmentioning

confidence: 99%

Microwave and Light-Wave Measurements for Nematic-Liquid-Crystal-Loaded Phase Shifter Using Coplanar Waveguide with Floating Electrode

Kamei

Moritake

Utsumi

2010

Jpn. J. Appl. Phys.

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We fabricated an experimental liquid-crystal-loaded coplanar waveguide with a floating electrode (CPW-FE) phase shifter with a straight-line structure and investigated its response time and phase characteristics by performing microwave measurements while varying structural parameters. We also constructed a liquid crystal optical cell using indium-tin-oxide (ITO) glass to simulate the CPW-FE structure and obtained measurements by capturing moving pictures using a polarized microscope. By comparing successive frames of this video and measuring response times to a steady state, we examined the behavior of liquid crystal molecules upon the application of a voltage to the liquid crystal layer. These observations enabled a qualitative physical interpretation of the results obtained by the above microwave measurements.

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Microwave High-Speed Liquid Crystal Devices Using CPW with Floating Electrode

Cited by 17 publications

References 4 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

Measurement of Dielectric Anisotropy of Some Liquid Crystals for Microwave Applications

Microwave and Light-Wave Measurements for Nematic-Liquid-Crystal-Loaded Phase Shifter Using Coplanar Waveguide with Floating Electrode

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