Analyses Of Dielectric Discontinuities In Waveguides By FEM/PML Method

The dielectric discontinuities in waveguides Eire analysed by finite element method (FEM) in combination with perfectly matched layers (PML). Firstly, the theoretical model of edge-based FEM for solving electromagnetic (EM) boundary value problems is outlined. A new method to truncate the computational area using PML absorbing boundary condition (ABC) is introduced. In the analyses of dielectric discontinuities in waveguides based on FEM, PML is equivalent to a lossy dielectric layer. In this way, the memory consumption is greatly reduced, and the boundary condition is simplified in deriving the equivalent functionals. The accuracy and efficiency of the FEM/PML method is demonstrated. Afterwards, several kinds of dielectric loaded waveguides are analyzed, including the waveguides loaded with multi-dielectric blocks, that partially filled with dielectric, and that loaded with anisotropic dielectrics. The simulated results of S parameter are presented. The influences of the permittivity on the S parameter is analyzed. Some useful conclusions have been deduced for the design of related microwave circuits. Finally some discussions are made on the performance of PML. The conclusions are valuable for the selections of the parameters of PML.