Frequency tunable S-band resonator using nematic liquid crystal

Yaghmaee, Pouria; Bates, B.; Manabe, Atsutaka; Karabey, Onur Hamza; Jakoby, Rolf

doi:10.1049/el.2012.1366

Cited by 25 publications

(22 citation statements)

References 6 publications

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“…To isolate the losses arising from the LC alone, the LC test device was first measured with an empty LC cavity (filled with air, ). The (indicating the attenuation due to radiation and superstrate) of the air-filled cell where is the attenuation due to the conductor losses in the empty LC cavity, is then subtracted from (denoting the attenuation due to LC, radiation, and superstrate), where is the conductor losses in the LC-filled cavity, to find (with a good approximation) the effective attenuation due to LC, (12) To derive (12), the attenuation due to conductor losses of the microstrip line in the LC section (cell) is assumed to be given by ; as indicated in the last paragraph of Section III. For the air-filled case, , and for the LC-filled case, .…”

Section: A Extraction Techniquementioning

confidence: 99%

“…This LC is relatively new, and therefore, this is the first time that such a broadband characterization is conducted on GT3-23001. However, some specific characterizations of GT3-23001 using resonator, frequency-selective-surface, and coaxial-line techniques are covered in [12], [32], and [33]. Especially, based on the resonator technique, reported in [12] are values of , , , and of GT3-23001 at 19 GHz and 1 kHz.…”

Section: Extraction Of Electrical Parameters Of Two Lcsmentioning

confidence: 99%

“…However, some specific characterizations of GT3-23001 using resonator, frequency-selective-surface, and coaxial-line techniques are covered in [12], [32], and [33]. Especially, based on the resonator technique, reported in [12] are values of , , , and of GT3-23001 at 19 GHz and 1 kHz. Comparing and from [12] with the present measured at the default (0 V) and switch-on (10.6 V) states at 19 GHz, Fig.…”

Section: Extraction Of Electrical Parameters Of Two Lcsmentioning

confidence: 99%

“…Especially, based on the resonator technique, reported in [12] are values of , , , and of GT3-23001 at 19 GHz and 1 kHz. Comparing and from [12] with the present measured at the default (0 V) and switch-on (10.6 V) states at 19 GHz, Fig. 12(a), respectively, it is revealed that the maximum difference between the two sets of data is 0.15 (corresponding to an average error of 5.3%).…”

Section: Extraction Of Electrical Parameters Of Two Lcsmentioning

confidence: 99%

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Microstrip Device for Broadband (15–65 GHz) Measurement of Dielectric Properties of Nematic Liquid Crystals

Deo

Mirshekar‐Syahkal

Seddon

et al. 2015

IEEE Trans. Microwave Theory Techn.

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The essential dielectric properties, the basic alignment techniques, and the common measurement methods of the nematic liquid crystal (LC) at RF are briefly reviewed. A new device for the broadband measurement of the dielectric constants and loss tangents of nematic LCs at microwave and millimeter-wave frequencies is presented. This device whose specification and fabrication are outlined is essentially a two dielectric layer microstrip structure with coplanar-waveguide terminals, which is easy to fabricate. Compared to previous structures, the proposed device is extremely broadband with 15-65-GHz bandwidth, benefits from a solid exposed ground plane for easy temperature test, and operates under bias voltage. The technique for the extraction of the dielectric parameters of the nematic LC analyzed by this device is explained and the sources imposing the frequency limits on the device performance are identified. Two different nematic LCs, MDA-00-3506 and GT3-23001, are characterized and the results are shown to compare well with those available in the literature. In the comparisons, the maximum difference found for the dielectric constants for MDA-00-3506 is 5% and for GT3-23001 is 5.3%.

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Section: A Extraction Techniquementioning

confidence: 99%

Section: Extraction Of Electrical Parameters Of Two Lcsmentioning

confidence: 99%

Section: Extraction Of Electrical Parameters Of Two Lcsmentioning

confidence: 99%

Section: Extraction Of Electrical Parameters Of Two Lcsmentioning

confidence: 99%

See 2 more Smart Citations

Microstrip Device for Broadband (15–65 GHz) Measurement of Dielectric Properties of Nematic Liquid Crystals

Deo

Mirshekar‐Syahkal

Seddon

et al. 2015

IEEE Trans. Microwave Theory Techn.

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“…The ELC resonator has been discussed as a building block for metamaterials absorbers, reflectors, modulators [1], [2] as well as microwave filters [3] and sensors [4], [5]. In this work the anisotropic properties of liquid crystals in their nematic phase [6] are exploited as a voltage-controlled tuning mechanism in an ELC resonator array. The liquid crystals fill a channel running through the ELC resonator capacitive gaps, in an arrangement that maximizes the interaction of concentrated fields with the liquid crystal molecules.…”

Section: Introductionmentioning

confidence: 99%

Tunable electric-LC resonators using liquid crystal

Yaghmaee

Withayachumnankul

Horestani

et al. 2013

2013 IEEE Antennas and Propagation Society International Symposium (APSURSI)

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A concept of tunable electric-LC (ELC) resonators is presented in this work. The voltage-controlled tunability is achieved by using liquid crystal in a micro-fluidic channel running through the central capacitive gaps. To attain the largest tunability, the structure is optimized through a parametric analysis using full-wave electromagnetic simulations. The simulation results predict a 6% continuous frequency tuning for this ELC resonator around the frequency of 4.5 GHz. The achieved results demonstrate the possibility of using these ELC resonators in an array to form a tunable frequency selective surfaces (FSS). The principle can be scaled for operation at higher microwave frequencies, where the dissipation of liquid crystal is low.

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Liquid‐Crystal High‐Frequency Microwave Technology: Materials and Characterization

Zografopoulos

Ferraro

Beccherelli

2018

Adv Materials Technologies

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Ever since the advent of microwave technology, tunable devices, such as phase shifters, resonators, and antennas, have been indispensable in applications requiring radiofrequency signal filtering, beam shaping, or steering. This necessity becomes even more relevant in view of a new era in high‐bandwidth wireless communications in 5G networks, satellite links, and advanced radars for sensing and safety. As the operating frequency is pushed toward the millimeter‐wave range or beyond, the performance of traditional microwave tunable elements, such as PIN diodes, micro‐electromechanical system switches, ferrites, or ferroelectric films, degrades, while their fabrication complexity and cost increases. In this respect, liquid crystals present a promising solution, as they provide continuous tuning, low dielectric constants, moderate losses, low dispersion, and potentially low cost. Here, a comprehensive overview of the available microwave liquid crystal materials is provided, including their key application‐relevant properties, and the techniques employed for their characterization, focusing on the spectrum above 1 GHz. Their performance metrics in terms of dielectric constant tunability, response speed, insertion losses are discussed and guidelines for their selection in different microwave applications are provided. Moreover, the differences observed in the experimental data regarding their characterization are highlighted and possible sources of the observed discrepancies are discussed.

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Frequency tunable S-band resonator using nematic liquid crystal

Cited by 25 publications

References 6 publications

Microstrip Device for Broadband (15–65 GHz) Measurement of Dielectric Properties of Nematic Liquid Crystals

Microstrip Device for Broadband (15–65 GHz) Measurement of Dielectric Properties of Nematic Liquid Crystals

Tunable electric-LC resonators using liquid crystal

Liquid‐Crystal High‐Frequency Microwave Technology: Materials and Characterization

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