Tunable frequency selective surface based on IDC-loaded electric-LC resonator incorporated with liquid crystal

Novin, Shohreh Nouri; Jarchi, Saughar; Yaghmaee, Pouria

doi:10.1109/comite.2017.7932364

Cited by 9 publications

(4 citation statements)

References 11 publications

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“…With the emergence and progress of newly developed LC mixtures specifically synthesized for microwaves since 2002 [45][46][47][48][49][50][51][52][53][54][55][56][57][58][59][60], innovative concepts and designs with appropriate biasing schemes enabled numerous high-performance MLC components and devices in the RF domain, which fully exploit the microwave LC's unique properties: various planar delay line, metallic and dielectric waveguide phase shifters at different frequencies [45][46][47], tunable resonators and filters [85][86][87][88][89][90][91][92][93][94][95][96][97][98][99], tunable power dividers and RF switches [80,[99][100][101][102][103][104], tunable metamaterial structures, frequency-selective and high-impedance surfaces [105][106][107][108][...…”

Section: Introductionmentioning

confidence: 99%

Microwave Liquid Crystal Enabling Technology for Electronically Steerable Antennas in SATCOM and 5G Millimeter-Wave Systems

Jakoby

Gaebler²,

Weickhmann³

2020

Crystals

102

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Future satellite platforms and 5G millimeter wave systems require Electronically Steerable Antennas (ESAs), which can be enabled by Microwave Liquid Crystal (MLC) technology. This paper reviews some fundamentals and the progress of microwave LCs concerning its performance metric, and it also reviews the MLC technology to deploy phase shifters in different topologies, starting from well-known toward innovative concepts with the newest results. Two of these phase shifter topologies are dedicated for implementation in array antennas: (1) wideband, high-performance metallic waveguide phase shifters to plug into a waveguide horn array for a relay satellite in geostationary orbit to track low Earth orbit satellites with maximum phase change rates of 5.1°/s to 45.4°/s, depending on the applied voltages, and (2) low-profile planar delay-line phase shifter stacks with very thin integrated MLC varactors for fast tuning, which are assembled into a multi-stack, flat-panel, beam-steering phased array, being able to scan the beam from −60° to +60° in about 10 ms. The loaded-line phase shifters have an insertion loss of about 3 dB at 30 GHz for a 400° differential phase shift and a figure-of-merit (FoM) > 120°/dB over a bandwidth of about 2.5 GHz. The critical switch-off response time to change the orientation of the microwave LCs from parallel to perpendicular with respect to the RF field (worst case), which corresponds to the time for 90 to 10% decay in the differential phase shift, is in the range of 30 ms for a LC layer height of about 4 µm. These MLC phase shifter stacks are fabricated in a standard Liquid Crystal Display (LCD) process for manufacturing low-cost large-scale ESAs, featuring single- and multiple-beam steering with very low power consumption, high linearity, and high power-handling capability. With a modular concept and hybrid analog/digital architecture, these smart antennas are flexible in size to meet the specific requirements for operating in satellite ground and user terminals, but also in 5G mm-wave systems.

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Section: Introductionmentioning

confidence: 99%

Microwave Liquid Crystal Enabling Technology for Electronically Steerable Antennas in SATCOM and 5G Millimeter-Wave Systems

Jakoby

Gaebler²,

Weickhmann³

2020

Crystals

102

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“…Generally speaking, required performance characteristics of an FSS are broader bandwidth, faster roll-off (sharp band edges), and stability with the variation of incident angles and polarizations of an incoming EM wave. It has been well identified from the earlier literature and in this review paper that the array element nature, its geometry, inter-element spacing, dielectric, and structure profiles are the defining structure parameters of an FSS [165]. Several critical challenges are to be addressed in successful designing of FSS structures.…”

Section: Future Challenges and Potential Applications Of Fsssmentioning

confidence: 98%

“…So, the development of novel types of FSSs without metallic composition is essential. Tunable FSSs are mainly based on liquid crystals [165][166][167], but the tuning ranges are comparatively limited, nevertheless still metallic screens are required to be embedded.…”

Section: Microwave Absorbing Fsssmentioning

confidence: 99%

Frequency Selective Surfaces: A Review

2018

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The intent of this paper is to provide an overview of basic concepts, types, techniques, and experimental studies of the current state-of-the-art Frequency Selective Surfaces (FSSs). FSS is a periodic surface with identical two-dimensional arrays of elements arranged on a dielectric substrate. An incoming plane wave will either be transmitted (passband) or reflected back (stopband), completely or partially, depending on the nature of array element. This occurs when the frequency of electromagnetic (EM) wave matches with the resonant frequency of the FSS elements. Therefore, an FSS is capable of passing or blocking the EM waves of certain range of frequencies in the free space; consequently, identified as spatial filters. Nowadays, FSSs have been studied comprehensively and huge growth is perceived in the field of its designing and implementation for different practical applications at frequency ranges of microwave to optical. In this review article, we illustrate the recent researches on different categories of FSSs based on structure design, array element used, and applications. We also focus on theoretical breakthroughs with fabrication techniques, experimental verifications of design examples as well as prospects and challenges, especially in the microwave regime. We emphasize their significant performance parameters, particularly focusing on how advancement in this field could facilitate innovation in advanced electromagnetics.

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“…Meanwhile, ultrathin periodic frequency selective surfaces (FSSs) deployed as electromagnetic wave absorbers have been a focus of research. Those planar single-layer structures are adapted to perfectly match free space impedance within various frequency ranges [4][5][6]. An ideal FSS absorber for the above-mentioned applications should realise near-unity absorption independent of the polarisation angle (ϕ) and incidence angle (θ) [1].…”

Section: Introductionmentioning

confidence: 99%

Planar wide‐angle and polarisation‐insensitive ultrathin frequency selective surface patch absorber design analysis and implementation

Abdalla

Hammad

2021

IET Microwaves Antenna & Prop

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Single-layer ultrathin absorber patch elements are analysed under normal and oblique incidence. A compensation technique for impedance variation with an angle of incidence (θ) is proposed. An equivalent-circuit model is formulated that provides a realisation for the absorption response (in terms of resonance frequency and absorption ratio) of noncomplicated rectangular patch absorbers using simple equations. The design methodology proposed is based on using multiple subcells of simple patches to add another degree of freedom for the design equations and keep the ultrathin planar feature. Previously reported techniques realising a wide angle of incidence are applied for fair comparison with the proposed methodology. The developed structure features angular stability, polarisation insensitivity, and a planar non-complicated configuration compared with that of structures reported in literature. Moreover, a prototype is fabricated and measured to validate the proposed approach.This is an open access article under the terms of the Creative Commons Attribution License, which permits use, distribution and reproduction in any medium, provided the original work is properly cited.

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Tunable frequency selective surface based on IDC-loaded electric-LC resonator incorporated with liquid crystal

Cited by 9 publications

References 11 publications

Microwave Liquid Crystal Enabling Technology for Electronically Steerable Antennas in SATCOM and 5G Millimeter-Wave Systems

Microwave Liquid Crystal Enabling Technology for Electronically Steerable Antennas in SATCOM and 5G Millimeter-Wave Systems

Frequency Selective Surfaces: A Review

Planar wide‐angle and polarisation‐insensitive ultrathin frequency selective surface patch absorber design analysis and implementation

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