Three dimension edge FEM analysis of inhomogeneous chiral medium loaded waveguide discontinuity

Dielectric-filled waveguides have important applications in many microwave devices, e.g., isolators and phase shifters. In these devices, there are always discontinuity for the constituent dielectrics in both shape and materials. Among them, the chiral medium is particularly receiving much interest because the chirality admittance provides one additional parameter that could make the practical designs more flexible. Traditionally, most of the investigations are based on the mode or field matching method with a particular class of geometries. It has been recognized that for a method to be useful as a good design tool, it must be capable of efficiently handling three-dimensional discontinuities with general configurations. Among the available techniques, the finite-element method (FEM) has been considered to be simplest in formulation and most flexible in modelling arbitrary shaped, inhomogeneously dielectric-filled discontinuity. In this FEM implementation, the use of tetrahedral edge-based vector finite elements is preferred because they are free from divergence, can model continuous tangential fields across dielectric interfaces or on conducting surface, and have small numerical dispersion. In this article the propagation/scattering properties of a chiral media partially filled waveguide are preliminarily investigated.