Design and application of a liquid crystal varactor based tunable coupled line for polarization agile antennas

Karabey, Onur Hamza; Bausch, Sara; Bildik, Saygin; Strunck, Sebastian; Gaebler, Alexander; Jakoby, Rolf

doi:10.23919/eumc.2012.6459335

Cited by 9 publications

(3 citation statements)

References 8 publications

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“…In a recent work, polarization agile antennas using liquid crystal mixtures (GT3-23001) were reported in [53,54] (Figure 8). This 2D beam steering phased array antenna consisted of a 2 by 2 dual-fed microstrip patch array and two separate feeding networks.…”

Section: Polarization Agile Antennasmentioning

confidence: 99%

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: Polarization Agile Antennasmentioning

confidence: 99%

Electrically Tuned Microwave Devices Using Liquid Crystal Technology

Yaghmaee

Karabey

Bates

et al. 2013

International Journal of Antennas and Propagation

Self Cite

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“…Such functionality can be used to realize high‐performance, co‐location receiving antenna in wireless channel measurement systems . The operation principle of dual CP square loop antennas can also be extended in the design of polarization‐reconfigurable or polarization‐agile antennas in various wireless sensor systems and applications. Furthermore, co‐linear embedded loop configurations could be employed to realize a wideband design .…”

Section: Resultsmentioning

confidence: 99%

Dual circularly polarized loop antenna using a pair of resonant even‐modes

Yuan

et al. 2019

Int J RF Microw Comput Aided Eng

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Conceptual design of dual circularly polarized (CP) square loop antennas using a pair of resonant even-modes for wireless sensor application is presented. A pair of even-modes is simultaneously excited within a single, nonuniform square loop element and employed to realize a dual circular polarization characteristic. When the natural boundary conditions of the even-modes and the feed lines are matched, respectively, a bidirectional dual CP loop antenna can be attained at first. Then, a unidirectional dual CP loop antenna is designed by introducing a simple metallic reflector. Both bidirectional and unidirectional designs exhibit dual CP performance with available operation bandwidth of 10.0% and 8.5%. The design approach is expected to get applications in dual CP antenna designs for wireless sensor systems. K E Y W O R D S dual circularly polarized antennas, even-mode resonant, square loop antenna 1 | INTRODUCTIONWireless sensors have been widely applied in wearable human activity recognition, 1 embedded sensing network, 2,3 home automation, 4 and so forth. The reliability of wireless signal transmission/reception in multipath fading, wireless sensing environments is always a critical challenge. CP antennas have been successfully employed to overcome the multipath effect and random polarization mismatching in wireless communications 5 and wearable sensing systems. 6 Although distributed CP diversity systems can be implemented by using a pair of CP antennas with opposite sensing, 6 dual CP antennas 7,8 would provide a co-location diversity transmitting/receiving functionality, and thus reduce the size, complexity and cost of wireless sensor systems. In the past few years, a series of dual CP antennas have been developed. These designs can be classified into three distinctive types according to their operation principles. The first type is the symmetrical perturbation 9,10 technique with enhanced compensation network 11 : Several symmetrical parasitic elements are stacked to the primary patch radiator, thus both LHCP and RHCP can be excited simultaneously. The second one is to use an additional 90 branch-line directional coupler. By connecting two orthogonal linearly polarized (LP) elements to the outputs of such couplers, RHCP and LHCP can be attained at the two mutually isolated inputs. [12][13][14][15][16] The third one is to enhance coupling with phase shifting network, 17-21 which can be recognized as the improved version of the two previous techniques.Basically, these techniques share one common characteristic that dual CP characteristic should be implemented by simultaneously exciting two orthogonal LP components with equal-magnitude and in/out phase-quadrature. Owing to introducing the techniques of symmetrical perturbations, 90 branch-line directional coupler, and phase shift networks, the resultant antennas are inevitably with high structural complexities having quite numerous parameters. As promising dual CP antenna designs with relatively simple structures, loop antennas have drawn more and more attenti...

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“…However, the phase tuning range and loss of LC based phase shifters have been less adequately investigated. 22) The objectives of this work is to (1) study the relationship between phase tuning range and insertion loss for low loss and high figure-of-merit (FoM) design of LC based phase shifters and (2) optimize the fabrication process of the designed devices.…”

Section: Introductionmentioning

confidence: 99%

High figure-of-merit compact phase shifters based on liquid crystal material for 1–10 GHz applications

Cai

et al. 2016

Jpn. J. Appl. Phys.

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A liquid crystal (LC) based tunable microstrip line (ML) phase shifter featuring high performance is presented. The experimental results show an electrically tunable differential phase up to 360° at 10 GHz with an overall insertion loss <8.5 dB. The device possesses a high figure-of-merit (FoM) of 64°/dB at 9.8 GHz and 60°/dB between 7–10 GHz. This is achieved by simultaneously considering both of the LC tuned phase and overall loss in the design. The proposed device utilizes the inverted meander ML technology to minimize its size. Taking into account the real fabrication procedure, a novel impedance matching structure is applied, and the measured return loss is considerably improved. The FoM and phase tuning property of the fabricated device as optimized are compared with the state-of-art results published recently and show better performance for both of them.

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Design and application of a liquid crystal varactor based tunable coupled line for polarization agile antennas

Cited by 9 publications

References 8 publications

Electrically Tuned Microwave Devices Using Liquid Crystal Technology

Electrically Tuned Microwave Devices Using Liquid Crystal Technology

Dual circularly polarized loop antenna using a pair of resonant even‐modes

High figure-of-merit compact phase shifters based on liquid crystal material for 1–10 GHz applications

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