A STUDY ON THE EIGENMODES OF THE SQUARE AND CIRCULAR COAXIAL WAVEGUIDES BY FEM

Abstract

FEM has been used to construct an eigen-equation for coaxial waveguides. Their cross sections have been square and circular shapes made with different dielectric constants. Krylov-Schur iteration method has been carried out to obtain the eigen-modes for these waveguides. The eigen-modes for each waveguides have been divided into two classes of TE and TM modes. These eigen-modes have been schematically represented with the spectra of transverse vector fields and their corresponding vector potential values. The spectra have shown the distribution of fields surrounding the interface between two dielectrics. Especially, the spectra have revealed the complicated distribution of field at the inner region of the dielectrics. As increased the distance from the center, the intensity of electromagnetic wave is decreased and arranged in the structured form. From these results, it could be identified that the eigen-modes seemed reflecting on the dielectric properties of coaxial waveguides.