Study on the Application of Liquid Crystals to Millimeter-Wave Controlling Devices

1.利用体效应二极管、衰减器、喇叭天线和毫米波探测器测量了向列相液晶盒的毫米波传输特性，工作频率分别为50 GHz和90 GHz。利用具有正介电各向异性的向列相液晶制备了均匀排列的液晶盒，并测量了它们在光学波长区的基本性质。从而得出在毫米波区域构建液晶器件的指导思想。测量了制备的液晶盒中毫米波传输特性的电压依赖关系，研究了毫米波极化与分子取向特性之间的关系。制作了具有栅状电极结构的向列相液晶单元，并测量了其毫米波传输特性。通过施加电压使液晶分子重新取向而引起的透射率的变化是ob…提供更多服务。提出了一种基于金属衬底、具有较大有效路径长度的粘贴层状结构的新型毫米波区域液晶单元。然后通过对电池施加电压，测量了47~53 GHz和86~94 GHz范围内的传输特性，可以获得较大的传输变化(~50%)。采用时域有限差分法(FDTD)研究了液晶层介电常数变化对液晶盒毫米波传输特性的频率依赖性。具有叠层结构的液晶棱镜和透镜是使用楔形和透镜形状的金属基板制备的。测量了毫米波偏转和聚焦特性，得到了偏转角和聚焦长度的变化。并用FDTD方法对这些影响进行了研究，实验结果与FDTD方法估算的结果基本一致。对研究结果进行了检验，并对研究工作进行了总结。较少

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 … More 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