Modélisation des effets des matériaux complexes anisotropes sur la propagation guidée en optohyperfréquence.

Abstract

The aim of our work is to study the propagation of electromagnetic waves in parallel plate waveguides with bi-anisotropic cores. However, we are interested in the first step to anisotropic chiral media, as media of an adequate effect on the characteristics of the structures treated. A theoretical study of electromagnetic wave propagation in guided structure is presented. The waveguide is filled with a chiral material having diagonal anisotropic constitutive parameters. The propagation characterization in this medium is based on algebraic formulation of Maxwell's equations combined with the constitutive relations. Three propagation regions are identified: the fast-fast-wave region, the fast-slow-wave region, and the slow-slowwave region. Our work focuses completely on the propagation in the first region, where the dispersion modal equations are obtained and solved. The cut-off frequencies calculation leads to three cases of the plane wave propagation in anisotropic chiral medium. The particularity of these results is the possibility of controlling the appropriate cut-off frequencies of the propagated modes by choosing the adequate physical parameters values of the substrate. The specificity of this study lies in the bifurcation modes confirmation, and the possible contribution to the design of optical devices such as high pass filters, as well as positive and negative propagation constants. This negative constant is an important feature of metamaterials which shows the phenomenon of backward waves. Original results of the biaxial anisotropic chiral metamaterial are obtained and discussed. In the second step of our research we are interested in the modeling of the propagation of the electromagnetic wave in another non-reciprocal Tellegen anisotropic medium. We have followed the same calculation steps as those of the anisotropic chiral medium, except that, the constitutive relations are as a function of the coupling parameter of the non-reciprocity. We have obtained the equations of decoupled electric and magnetic waves, and dispersion equations of Tellegen anisotropic, Tellegen isotropic and Tellegen nihility medium. A comparison between propagation in both media (Tellegen and chiral) is presented in a table.