| Research Abstract |
1. The millimeter-wave (MMW) transmission properties of the nematic liquid crystal cells are measured using a Gunn diode, attenuator, horn-antenna and MMW detector, in which the operating frequencies are 50GHz and 90GHz band.
2. The homogeneously aligned liquid crystal cells are prepared using nematic liquid crystal with a positive dielectric anisotropy, and their fundamental properties in the optical wavelength region are measured. Then the guideline for constructing the liquid crystal devices in the MMW region can be obtained.
3. The voltage dependence of MMW transmission properties in the prepared liquid crystal cells are measured and the relationship between the polarization of MMW and molecular orientation properties is studied.
4. Nematic liquid crystal cells with a grating-patterned electrode structure are fabricated and the MMW transmission properties are measured. The changes in the transmission induced by the reorientation of liquid crystal molecules by applying a voltage are ob
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served.
5. Novel liquid crystal cells with a stuck-layered structure using metal substrates, which have a large effective path length, are proposed for the MMW region. Then the transmission properties are measured from 47 to 53 GHz and 86 to 94 GHz ranges by applying a voltage to the cell, and large transmission changes (〜50%) can be obtained.
6. The finite-difference time-domain (FDTD) method is implemented to study the frequency dependence of the MMW transmission properties of the liquid crystal cell caused by the change in the dielectric permittivity of the liquid crystal layer.
7. The liquid crystal prism and lens with a stack-layered structure are prepared using wedge-shaped and lens shaped metal substrates. The MMW deflection and focusing properties are measured, and the changes in the deflection angle and focusing length can be obtained. These effects are also studied by the FDTD method, and the experimental results are consistent with those estimated by the FDTD method.
8. The results are examined and the research work is summarized. Less
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