Potential of Liquid-Crystal Materials for Millimeter-Wave Application

Nose, Toshiaki; Ito, Ryo; Honma, Mareki

doi:10.3390/app8122544

Cited by 11 publications

(6 citation statements)

References 53 publications

(73 reference statements)

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“…The large optical anisotropies of nematic LCs in the MMW region (birefringence and dichroism) are attractive for the realization of various electrically controllable LC devices [31] - [33]. The usual planar alignment LC cell can vary the MMW transmittance with respect to applied voltage because the absorption amount depends on the LC orientation direction.…”

Section: Lc Mask Cell and Driving Circuitmentioning

confidence: 99%

Millimeter-Wave Single-Pixel Imaging Using Electrically-Switchable Liquid-Crystal Mask

Honma

Sase

Ito

et al. 2023

IEICE Trans. Electron.

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In this study, we have proposed a millimeter-wave (MMW) single-pixel imaging (SPI) system with a liquid-crystal (LC) mask cell. The LC cell functions as an electrically switchable mask based on the change in absorption properties, which depend on the orientation of the LC. We investigated the influence of noise on the measured and estimated data (reconstructed image). The proposed system exhibited moderate robustness against random noise (that were added) compared to raster scan-based and Hadamard matrix-based SPI systems. Finally, the results of some demonstrative experiments were introduced to ensure the applicability of the constructed MMW-SPI system, and steps for improving the reconstructed image quality were discussed.

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Section: Lc Mask Cell and Driving Circuitmentioning

confidence: 99%

Millimeter-Wave Single-Pixel Imaging Using Electrically-Switchable Liquid-Crystal Mask

Honma

Sase

Ito

et al. 2023

IEICE Trans. Electron.

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“…The LC mixture used in this work is GT7-29001 from Merck KGaA, Darmstadt, Germany. A broad spectrum of LC-based components, such as filters [7,8], phase shifters and antennas [9][10][11] in different topologies and at various frequencies has been presented. Especially phase shifters are key components for phase correction or phase manipulation in phased-array applications.…”

Section: Introductionmentioning

confidence: 99%

Temperature Characterization of Liquid Crystal Dielectric Image Line Phase Shifter for Millimeter-Wave Applications

et al. 2021

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In this paper we investigate the temperature dependent behavior of a liquid crystal (LC) loaded tunable dielectric image guide (DIG) phase shifter at millimeter-wave frequencies from 80 GHz to 110 GHz for future high data rate communications. The adhesive, necessary for precise fabrication, is analyzed before temperature dependent behavior of the component is shown, using the nematic LC-mixture GT7-29001. The temperature characterization is conducted by changing the temperature of the LC DIG’s ground plane between −10∘C and 80 ∘C. The orientation of the LC molecules, and therefore the effective macroscopic relative permittivity of the DIG, is changed by inserting the temperature setup in a fixture with rotatable magnets. Temperature independent matching can be observed, while the insertion loss gradually increases with temperature for both highest and lowest permittivity of the LC. At 80 ∘C the insertion loss is up to 1.3dB higher and at −10∘C it is 0.6dB lower than the insertion loss present at 20 ∘C. In addition, the achievable differential phase is reduced with increasing temperature. The impact of molecule alignment to this reduction is shown for the phase shifter and an estimated 85% of the anisotropy is still usable with an LC DIG phase shifter when increasing the temperature from 20 ∘C to 80 ∘C. Higher reduction of differential phase is present at higher frequencies as the electrical length of the phase shifter increases. A maximum difference in differential phase of 72∘ is present at 110 GHz, when increasing the temperature from 20 ∘C to 80 ∘C. Nevertheless, a well predictable, quasi-linear behavior can be observed at the covered temperature range, highlighting the potential of LC-based dielectric components at millimeter wave frequencies.

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“…To better illustrate the breadth of this application, one should look at the spectrum of electromagnetic radiation. LCs are used in devices operating in visible light, infrared (IR) [ 5 ], millimeter wave [ 6 , 7 , 8 , 9 , 10 ], terahertz [ 11 , 12 , 13 , 14 ], and gigahertz [ 15 , 16 , 17 , 18 ].…”

Section: Introductionmentioning

confidence: 99%

New-Generation Liquid Crystal Materials for Application in Infrared Region

Harmata

Herman

2021

Materials

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This study presents 13 new organic compounds with self-assembling behavior, which can be divided into two groups. The first synthesized group includes compounds based on 4′-(trifluoromethoxy)-[1,1′-biphenyl]-4-yl-4-(trifluoromethoxy) benzoate core, and the second includes compounds based on 4-((4-(trifluoromethoxy)phenyl)ethynyl)phenyl-4-(trifluoromethoxy) benzoate core. They differ in the number and location of the fluorine atom in the lateral position. Mesomorphic properties, phase transition enthalpies, refractive indices, birefringence, and MWIR (mid-wavelength infrared) spectral properties of the compounds were investigated, and the results were compared with currently used materials. The influence of the length of the core as well as type and position of substituents in the molecular core was analyzed. The lack of aliphatic protons in the molecular structure generated unique infrared properties.

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Potential of Liquid-Crystal Materials for Millimeter-Wave Application

Cited by 11 publications

References 53 publications

Millimeter-Wave Single-Pixel Imaging Using Electrically-Switchable Liquid-Crystal Mask

Millimeter-Wave Single-Pixel Imaging Using Electrically-Switchable Liquid-Crystal Mask

Temperature Characterization of Liquid Crystal Dielectric Image Line Phase Shifter for Millimeter-Wave Applications

New-Generation Liquid Crystal Materials for Application in Infrared Region

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