Comparative analysis of scattering matrix calculation of dielectric waveguide discontinuity models by using FEM solution of two dimensional Helmholtz equations

A simple method is a FEM solution of two dimensional Helmholtz equations is developed in this paper. For calculating reflection and transmission coefficient of electromagnetic energy in the waveguide structure by varying frequency of input wave and diameter and length of waveguide by using relations K=π/d and f=KV/2π. The first step is modeling of waveguide by using finite element method and then scattering matrix and other parameters are obtained by using two dimensional Helmholtz equations. Model with 90deg double bend type discontinuity with two stages are modeled and scattering and other parameters are calculated and results are compared with multi step type waveguide discontinuity with three stages and finally two and three stages of wave propagation are studied and analyzed.