Broad band electromagnetic characterization method of nematic liquid crystals using a coplanar waveguide

A broad band electromagnetic extraction method of the dielectric tensor for nematic liquid crystals, associated to a measuring cell, is presented. The dielectric tensor is computed from S-parameter measurements obtained at the input planes of a coplanar waveguide supporting the nematic liquid crystal to be characterized, which is used as measuring cell. The extraction method of the dielectric tensor is based on the propagation of the dominant mode in the measuring cell. It is fast and easy. It uses analytical relationships, which are presented in this paper. The simulations results have demonstrated the validity of this extraction method in the 1GHz-40GHz frequency range for the electromagnetic characterization of nematic liquid crystals. J. Hinojosa is grateful to Ministerio de Ciencia y Technología and Region de Murcia Fundación Séneca of Spain for the grants TIC2002-01266 and PB/39/FS/02, which have allowed the present research activity.