Free Space Method for Measurement of Millimeter-Wave Dielectric Properties of Liquid Crystals

Liquid crystal (LC) is a promising anisotropic dielectric material for designing reconfigurable devices at microwave and millimeter-wave frequencies. The free space method is used for the characterization of anisotropic properties of LC without applying any external electric or magnetic field at 75 GHz~110 GHz. A two-tier calibration and a de-embedding method are employed to extract two extreme permittivity values. The results show that the test LC sample has obvious positive anisotropy in the millimeter-wave frequencies with the tunability up to 19%.