Tunable liquid crystal phase shifter for microwave frequencies

Goelden, F.; Gaebler, Alexander; Goebel, M.; Manabe, Atsutaka; Mueller, Stefan; Jakoby, Rolf

doi:10.1049/el.2009.1168

Cited by 66 publications

(42 citation statements)

References 3 publications

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“…In a different example, reducing the liquid crystal cell thickness was discussed as a technique for improving tuning/switching speed [37]. In this work, using only 5 m thickness of liquid crystals instead of the more common 500 m resulted in 60 ∘ of phase shift with a tuning speed of 340 ms. Dual-frequency switching mode was proposed for active alignment of the liquid crystal molecules in two principal directions [38].…”

Section: Phase Shifters and Delay Linesmentioning

confidence: 94%

Electrically Tuned Microwave Devices Using Liquid Crystal Technology

Yaghmaee

Karabey

Bates

et al. 2013

International Journal of Antennas and Propagation

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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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Section: Phase Shifters and Delay Linesmentioning

confidence: 94%

Electrically Tuned Microwave Devices Using Liquid Crystal Technology

Yaghmaee

Karabey

Bates

et al. 2013

International Journal of Antennas and Propagation

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“…To improve the phase shifter performance, more resistive material for biasing line, i.e. Indium tin oxide (ITO), and less lossy glass, i.e., Fused silica [7] may be used as in [7].…”

Section: B Simulation and Measurement Resultsmentioning

confidence: 99%

“…A properly designed topology should fully utilize the tunability of LC to achieve a high tuning efficiency while reducing the device's response time down to a few seconds. In [7] and [8], LC varactor loaded coplanar waveguides and slotlines have been respectively studied to reduce the response time. Unlike to these aforementioned works, here, a microstrip line is loaded with varactors, which features system-inherently low losses [9] compared to coplanar waveguide (CPW) and slotline.…”

Section: Introductionmentioning

confidence: 99%

Liquid crystal varactor loaded variable phase shifter for integrated, compact, and fast beamsteering antenna systems

Hu¹,

Karabey²,

Gabler³

et al. 2014

2014 9th European Microwave Integrated Circuit Conference

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This paper presents a microstrip variable delay line loaded with liquid crystal varactors in series. The design of the device, including both the theoretical analysis and the fabrication, is presented. The proposed design shows a high LC varactor tuning efficiency of 83% and a low response time in the order of 3 seconds. These high performances result from implementing the varactors in parallel plate capacitor topology and with a 10 μm thick LC layer as a tunable dielectric between the electrodes. Simulation and measurement results verify that a designed prototype can provide a differential phase shift of 60°a t 20 GHz with an insertion loss no higher than 2 dB.This work presents an LC varactor loaded microstrip vari-978-2-87487-036-1

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“…However, the application of liquid crystal in non-display has also been great development since 21st century, especially the liquid crystal microwave modulator. [1][2][3][4][5][6][7][8][9][10][11][12][13] The microwave modulation property of liquid crystal is based on the fact discovered by K. C. Lim et al 14 that many liquid crystal materials retain considerable anisotropy of the permittivity and optical birefringence in microwave bands of electromagnetic radiation which has ever been reported in later literatures. [15][16][17][18] Then, Masaki Tanaka et al and Hideo Fujikake et al have manufactured the liquid crystal phase shifters by controlling the distribution of director in cell using the grating electrode structure 1 and the photopolymerization induced phase separation technology, 3 respectively.…”

Section: Introductionmentioning

confidence: 99%

Influence of rubbing-alignment on microwave modulation induced by liquid crystal

Xing

Zhou

et al. 2015

AIP Advances

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The microwave modulation induced by liquid crystal is decided by the liquid crystal director distribution under an external applied voltage. The rubbing-alignment of substrate has an effect on the liquid crystal director, which must result in the change of microwave phase-shift. To illustrate the influence of rubbing-alignment on the microwave phase-shift, the microwave modulation property of twisted nematic liquid crystal is researched adopting the elastic theory of liquid crystal and the finite-difference iterative method. The variations of microwave phase-shift per unit-length for different pre-tilt and pre-twist angles of liquid crystal on the substrate surface and anchoring energy strengths with the applied voltage are numerically simulated. The result indicates that with the increase of pre-tilt angle and with the decrease of anchoring energy strength the weak anchoring twisted cell with pre-twisted angle 90° relative to the strong anchoring non-twisted cell can increase the microwave phase-shift per unit-length. As a result, for achieving the maximum microwave modulation, the weak anchoring twisted cell with pre-tilt angle 5° and anchoring energy strength 1×10−5J/m2 should be selected, which provides a reliably theoretical foundation for the design of liquid crystal microwave modulator.

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Tunable liquid crystal phase shifter for microwave frequencies

Cited by 66 publications

References 3 publications

Electrically Tuned Microwave Devices Using Liquid Crystal Technology

Electrically Tuned Microwave Devices Using Liquid Crystal Technology

Liquid crystal varactor loaded variable phase shifter for integrated, compact, and fast beamsteering antenna systems

Influence of rubbing-alignment on microwave modulation induced by liquid crystal

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