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

Kamei, Takeshi; Moritake, Hiroshi; Utsumi, Yozo

doi:10.1143/jjap.49.01af03

Cited by 10 publications

(7 citation statements)

References 8 publications

(8 reference statements)

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“…We did a pilot study [3] on the tuning range limit of the FE-free CPW structure parameterized with geometrical aspect ratios and pointed out that such thin-Cu patterned structure suffers from low wave-occupied volume ratio of tunable LC to nontunable substrates, while a countermeasure we proposed using thick-Cu patterning and surface anchoring inside a deep channel challenged the status of precision manufacturing and LC alignment technology. Instead, the CPW-FE structure with a floating electrode on top [20][21][22][23] modulated the LC predominately at a planar cavity with the wave largely occupying tunable dielectrics, and, hence, reasonably higher tuning ranges and phase shifts were reported at microwave frequencies. A periodically loaded CPW-FE segments approach [24] reported a figure-of-merit of 60°/dB at 20 GHz with response times in the range of 110 ms-340 ms for LC layer thickness of 4 µm.…”

Section: Introductionmentioning

confidence: 99%

Liquid Crystal-Based Enclosed Coplanar Waveguide Phase Shifter for 54–66 GHz Applications

Chu

2019

Crystals

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A 0–10 V bias voltage-driven liquid crystal (LC) based 0°–180° continuously variable phase shifter was designed, fabricated, and measured with insertion loss less than −4 dB across the spectrum from 54 GHz to 66 GHz. The phase shifter was structured in an enclosed coplanar waveguide (ECPW) with LC as tunable dielectrics encapsulated by a unified ground plate in the design, which significantly reduced the instability due to floating effects and losses due to stray modes. By competing for spatial volume distribution of the millimeter-wave signal occupying lossy tunable dielectrics versus low-loss but non-tunable dielectrics, the ECPW’s geometry and materials are optimized to minimize the total of dielectric volumetric loss and metallic surface loss for a fixed phase-tuning range. The optimized LC-based ECPW was impedance matched with 1.85 mm connectors by the time domain reflectometry (TDR) method. Device fabrication featured the use of rolled annealed copper foil of lowest surface roughness with nickel-free gold-plating of optimal thickness. Measured from 54 GHz to 66 GHz, the phase shifter prototype presented a tangible improvement in phase shift effectiveness and signal-to-noise ratio, while exhibiting lower insertion and return losses, more ease of control, and high linearity as well as lower-cost fabrication as compared with up-to-date documentations targeting 60 GHz applications.

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Section: Introductionmentioning

confidence: 99%

Liquid Crystal-Based Enclosed Coplanar Waveguide Phase Shifter for 54–66 GHz Applications

Chu

2019

Crystals

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“…Th e combination of periodic metal surfaces with LCs provides the possibility of tuning their plasmonic properties by an external electric fi eld [1][2][3]. Metal/ LC interfaces are employed as tunable microwave and IR devices [4][5][6].…”

Section: Introductionmentioning

confidence: 99%

“…Th e absorbance spectra of the granular silver fi lms on the top of ITO/a-C:H thin multilayer fi lms before (1, 3) and aft er annealing(2,4) at 200°C on glass substrates and at the interface in LC cells.…”

mentioning

confidence: 99%

Effect of Granular Silver Films Morphology on the Molecules Orientation and Ion Contamination of Nematic Liquid Crystal

Konshina

Shcherbinin

2017

Bulletin of the MSRU (Physics and Mathematics)

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The structure of granular silver films at the interface of liquid crystal (LC) cells and their influence on LC molecule orientation and ionic contamination are examined. Granular silver films were deposited on a glass substrate covered with an ITO electrode and a-C:H thin films. The morphology structure of the silver films was changed after their annealing at 200 °C. The silver granules became spheroidal with an average diameter of-30 nm and the channel area between them increased. The change in the structure of the Ag films led to an increase in the phase retardation and a decrease in the pretilt angle of the LC director from 51° to 7°. The density of ionic impurities in the LC cell with the annealed silver film was three times more than in the LC cell with the unannealed film. The impact of the alignment of the LC molecules at the surface of the granular silver films on the intensity of the plasmonic peak and its red shift in the absorption spectra is shown.

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“…[2][3][4][5][6][7][8][9][10] The properties of microwave devices with various types of transmission line and liquid crystal have been studied. Examples of such devices are a microwave phase shifter using a microstripline (MSL) loaded with a liquid crystal, [11][12][13] a microwave variable phase shifter using a coplanar waveguide loaded with a liquid crystal, [14][15][16][17][18] and a microwave phase shifter using a rectangular waveguide loaded with a liquid crystal. 19) Both experiments and theoretical calculations were performed in these studies.…”

Section: Introductionmentioning

confidence: 99%

Analyses of Nematic Liquid Crystal Molecule Motion and Response Characteristics in Microstripline-Type Microwave Phase Shifter

Nguyễn

Nguyen

Ozaki

et al. 2013

Jpn. J. Appl. Phys.

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In this paper, we propose an improved calculation method for analyzing the three-dimensional motion of nematic liquid crystal molecules in studies of all types of microwave transmission line loaded with a nematic liquid crystal. This method is applied to the analysis of motion of nematic liquid crystal molecules under a nonuniformly distributed electric field generated by asymmetric electrodes in a microstripline structure as a comprehensive example. Then, the dielectric constant distribution of the nematic liquid crystal layer, the effective dielectric constant in a microwave electric field, and the phase shift of a microwave in the microstripline loaded with a nematic liquid crystal are calculated. The rise time, decay time, and phase shift of a microwave phase shifter using a microstripline loaded with a nematic liquid crystal are also calculated. The differences in these response characteristics and their dependences on the width of the center conductor of the microstripline are determined by calculation and confirmed by performing experiments on the microwave phase shifters and an optical experiment on the retardation of the microstripline loaded with a nematic liquid crystal structure.

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

Cited by 10 publications

References 8 publications

Liquid Crystal-Based Enclosed Coplanar Waveguide Phase Shifter for 54–66 GHz Applications

Liquid Crystal-Based Enclosed Coplanar Waveguide Phase Shifter for 54–66 GHz Applications

Effect of Granular Silver Films Morphology on the Molecules Orientation and Ion Contamination of Nematic Liquid Crystal

Analyses of Nematic Liquid Crystal Molecule Motion and Response Characteristics in Microstripline-Type Microwave Phase Shifter

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