A study of effective permittivity for thermotropic liquid crystals in 7.8-12.4 GHz frequency range

A liquid crystal study was performed, in order to determine the relative effective electric permittivity, using a microwave simulation method. Three thermotropic types of liquid crystals: nematic, smectic and cholesteric were considered and their structures were simulated with the help of a microwave simulation program: high frequency structure simulator (HFSS - Ansoft Technologies). An analysis method based on physical considerations for the calculation of the effective permittivity of the considered structures was used for the frequency range 7.8-12.4 GHz, where the precision of the method is the best The results were commented from the point of view of effective permittivity dependence of the samples internal structures (geometry) and frequency behavior.