Isotropic and gyrotropic chiral composite materials: dispersion and negative refractive index

This paper focuses on not only the isotropic chiral but also gyrotropic chiral materials with primary interest in dispersion, realization of double negative materials (DNG) and negative refractive index. To take into account the dispersion, the Condon model together with Tellegen´s definition of chiral media is used for the frequency dependence of three parameters (permittivity, permeability and chirality). We also consider the equivalent permittivity and permeability of isotropic chiral media which is frequency dependent. As a generalized case, gyrotropic chiral media is studied since the gyrotropic parameters in epsilowbar and mulowbar tensors favor the realization of DNG and negative-index materials (NIM)