Eigenvalue Analysis for Two-Dimensional Discontinuous Waveguides

Classical finite element method has been widely used in solving various waveguide and resonator problems. However, the filled dielectric material or the joint of the waveguide is possibly no longer uniform when the waveguide structure or material is irregular. In this case, the traditional two-dimensional port method will need to deal with following problems, such as boundary matching, energy loss and so on. In order to better achieve waveguide transmission, this paper presents a new eigenvalue analysis for two-dimensional discontinuous waveguides. Firstly, we adopt hybrid basis function form of scalar and vector basis functions to discrete a generalized eigenvalue equation. Secondly, we give a specific implementation of impedance boundary conditions, which can deal with some complex geometry and discontinuous materials. Compared with the traditional waveguide port matching technique, this proposed method can effectively solve the generalized eigenvalue equation, especially for lossy physical problems. Numerical results show that attenuation constant is in accordance with the HFSS software, which illustrates that this method is very convenient for simulation and design of discontinuous waveguide problems.