Method for determination of nematic liquid crystals (NLC) anisotropy dielectric permittivity is reviewed in this article. Determination of this value is accessed by measuring small changes in resonance frequency and Q-factor of SHF cavity loaded with NLC with applied frequency modulation. This method is based on analysis of envelope signal spectrum obtained from cavity under frequency modulation. Frequency modulation of feeding generator is provided according to harmonic law with frequency deviation of the same order of magnitude as cavity transmission band. Results provided for anisotropy measurements of nematic liquid crystals (NLC class 5-CB) by means of cylindrical cavity with 3 cm range and Е101 oscillations.
anisotropy of dielectric permitability, nematic liquid crystal, SHF-cavity, frequency modulation