A STUDY ON THE EIGEN - MODE INFLUENCED BY THE INTERFACE BETWEEN TWO DIFFERENT DIELECTRICS

FEM has been carried out to investigate the eigen - mode of a square cross section waveguide filled with two different dielectrics. Vector Helmholtz equation was re - configured as transverse spa ce dependent form to facilitate FEM. The eigen - equation of FEM w as established from element equations of triangular mesh. For the transverse vectot field, the equation was constructed using tangential edges of the element mesh. The equation for the transverse vector potential component was made basing on its nodal points . These equations were combined into a gloval square matrix to calculate the eigen - modes. TE and TM eigen - modes influenced by the interface were obtained using the Krylov - Schur iteration method. As a result, each transverse vector fields and their vector potential component have been revealed by schematic representation to identify their physical propert y . And spectra of TM eigen - mode were compared with results of the theoretica l calculation.