Determination of the microwave permittivities of nematic liquid crystals using a single-metallic slit technique

A technique is presented for quantifying the microwave permittivities of small quantities of material. Here a 75 mum gap between two 3 mm thick aluminum plates is filled with a nematic liquid crystal. This filled slit is inserted in an absorber aperture. A set of transmission peaks are recorded as a function of incident wavelength for microwaves polarized with their electric field perpendicular to the slit direction. When a voltage is applied between the two plates, the liquid crystal realigns and the shift of the resonant peaks gives the anisotropic permittivities of the nematic material in the microwave region. (C) 2002 American Institute of Physics.