Design and Simulation of Tunable Phase Shifters Based on Liquid Crystals

Unconventional folded shielded coplanar waveguide (FS-CPW) has yet to be fully investigated for tunable dielectrics-based applications. This work formulates designs of FS-CPW based on liquid crystals (LC) for electrically controlled 0-360˚ phase shifters, featuring a minimally redundant approach for reducing the LC volume and hence the costs for mass production. The design exhibits a few conceptual features that make it stand apart from others, noteworthy, the dual-strip structure with a simplified enclosure engraved that enables LC volume sharing between adjacent core lines. Insertion loss reduction by 0.77 dB and LC volume reduction by 1.62% per device are reported at 77 GHz, as compared with those of the conventional single-strip configuration. Based on the proof-of-concept results obtained for the novel dual-strip FS-CPW proposed, this work provides a springboard for follow-up investible propositions that will underpin the development of a phased array demonstrator.

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High-Transmittance 2π Electrically Tunable Terahertz Phase Shifter with CMOS-Compatible Driving Voltage Enabled by Liquid Crystals

Applied Sciences ◽

10.3390/app9020271 ◽

2019 ◽

Vol 9 (2) ◽

pp. 271 ◽

Cited By ~ 4

Author(s):

Chan-Shan Yang ◽

Chun Kuo ◽

Po-Han Chen ◽

Wei-Ta Wu ◽

Ru-Pin Pan ◽

...

Keyword(s):

Liquid Crystals ◽

Tin Oxide ◽

Indium Tin Oxide ◽

Phase Shifter ◽

Quartz Substrate ◽

Phase Shifters ◽

Driving Voltage ◽

Cmos Compatible ◽

Pretilt Angles ◽

Good Agreement

We have investigated tunable terahertz (THz) phase shifters that are based on a sandwiched liquid crystal (LC) cell with indium–tin–oxide (ITO) nanowhiskers (NWhs) as transparent electrodes. More than 360° of phase shift at 1.0 THz was achieved at a driving voltage as low as ~2.6 V (rms). This is approximately 40 times smaller than that reported in previous works using an electrically tuned LC device. Significance of the NWhs in reducing the required voltage is demonstrated. Overall transmittance of the device is as high as 30%, which is accountable by absorption losses of ITO NWhs, quartz substrate and LC. Experimental results are in good agreement with a theoretical formulism while taking into account super-thick LC cells (~1 mm) and pretilt angles. We also propose and demonstrate a novel THz technique for measuring pretilt angles of liquid crystals.

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Rethinking Figure-of-Merits of Liquid Crystals Shielded Coplanar Waveguide Phase Shifters at 60 GHz

J ◽

10.3390/j4030034 ◽

2021 ◽

Vol 4 (3) ◽

pp. 444-451 ◽

Cited By ~ 1

Author(s):

Jinfeng Li

Keyword(s):

Liquid Crystals ◽

Insertion Loss ◽

Phase Shifter ◽

Coplanar Waveguide ◽

Volume Ratio ◽

Phase Shifters ◽

60 Ghz ◽

Two Phase ◽

Differential Phase Shift ◽

Millimetre Wave

The demand for reconfigurable millimetre-wave (mm-Wave) components based on highly anisotropic liquid crystals (LC) is higher than ever before for the UK and worldwide. In this work, 60 GHz investigation on a bespoke shielded coplanar waveguide (SCPW) phase shifter structure filled with 16 types of microwave-enabled nematic LCs respectively indicates that the patterns of the device’s figure-of-merit (FoM, defined as the ratio of maximum differential phase shift to maximum insertion loss) reshuffle from those of the characterised LC materials’ FoM (defined as the ratio of tunability to maximum dissipation factor). To be more specific, GT7-29001- and MDA-03-2838-based phase shifters exhibit the highest FoM for devices, outperforming phase shifters based on GT5-28004 and TUD-566 with the highest FoM for materials. Such a mismatch between the device’s FoM and LC’s FoM implies a nonlinearly perturbed wave-occupied volume ratio effect. Furthermore, the relationship between insertion loss and the effective delay line length is nonlinear, as evidenced by measurement results of two phase shifters (0–π and 0–2π, respectively). Such nonlinearities complicate the established FoM metrics and potentially lead to a renewed interest in the selection and material synthesis of LCs to optimise reconfigurable mmWave devices, and promote their technological exploitation in phased array systems targeting demanding applications such as inter-satellite links and satellite internet.

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Electrically Tuned Microwave Devices Using Liquid Crystal Technology

International Journal of Antennas and Propagation ◽

10.1155/2013/824214 ◽

2013 ◽

Vol 2013 ◽

pp. 1-9 ◽

Cited By ~ 36

Author(s):

Pouria Yaghmaee ◽

Onur Hamza Karabey ◽

Bevan Bates ◽

Christophe Fumeaux ◽

Rolf Jakoby

Keyword(s):

Liquid Crystal ◽

Liquid Crystals ◽

Physical Theory ◽

Phase Shifters ◽

Low Power Consumption ◽

Frequency Selective Surfaces ◽

Delay Lines ◽

Liquid Crystal Devices ◽

Continuous Tuning ◽

Liquid Crystal Technology

An overview of liquid crystal technology for microwave and millimeter-wave frequencies is presented. The potential of liquid crystals as reconfigurable materials arises from their ability for continuous tuning with low power consumption, transparency, and possible integration with printed and flexible circuit technologies. This paper describes physical theory and fundamental electrical properties arising from the anisotropy of liquid crystals and overviews selected realized liquid crystal devices, throughout four main categories: resonators and filters, phase shifters and delay lines, antennas, and, finally, frequency-selective surfaces and metamaterials.

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The Structure and Development of Microbodies in the Fat Body and other Tissues of an Insect (Calpodes Ethlius)

Proceedings, annual meeting, Electron Microscopy Society of America ◽

10.1017/s042482010006773x ◽

1970 ◽

Vol 28 ◽

pp. 148-149

Author(s):

M. Locke ◽

J. T. McMahon

Keyword(s):

Electron Microscopy ◽

Liquid Crystals ◽

Fat Body ◽

Competitive Inhibitor ◽

Dense Core ◽

Urate Oxidase ◽

Blood Proteins ◽

Free Base ◽

The Core ◽

The Matrix

The fat body of insects has always been compared functionally to the liver of vertebrates. Both synthesize and store glycogen and lipid and are concerned with the formation of blood proteins. The comparison becomes even more apt with the discovery of microbodies and the localization of urate oxidase and catalase in insect fat body.The microbodies are oval to spherical bodies about 1μ across with a depression and dense core on one side. The core is made of coiled tubules together with dense material close to the depressed membrane. The tubules may appear loose or densely packed but always intertwined like liquid crystals, never straight as in solid crystals (Fig. 1). When fat body is reacted with diaminobenzidine free base and H2O2 at pH 9.0 to determine the distribution of catalase, electron microscopy shows the enzyme in the matrix of the microbodies (Fig. 2). The reaction is abolished by 3-amino-1, 2, 4-triazole, a competitive inhibitor of catalase. The fat body is the only tissue which consistantly reacts positively for urate oxidase. The reaction product is sharply localized in granules of about the same size and distribution as the microbodies. The reaction is inhibited by 2, 6, 8-trichloropurine, a competitive inhibitor of urate oxidase.

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