Circular Chiroferrite Waveguides: Dispersion Curves and Dyadic Green's Functions

Abstract

In this paper, the eigenmodes in circular chiroferrite waveguides are studied and the dyadic Green's functions are derived for the first time. The electric and magnetic fields are expanded by cylindrical vector wave eigenfunctions. It is shown that each of the eigenmodes consists of two eigenwaves corresponding to two different polarizations. A dispersion relation is obtained by imposing boundary conditions on the eigenmodes, and the dispersion curves are depicted for various medium parameters. The effects of the uniaxial anisotropy, the gyrotropy, and the chirality are discussed individually. The mode orthogonality is built by introducing complementary testing modes. Hence, the expansion coefficients of the electric and magnetic fields are determined and the dyadic Green's functions are formulated. In order to obtain the complete expansions of the dyadic Green's functions, the singularities of chiroferrite waveguides are also discussed.