Analysis Of Electromagnetic Problems In Complicated Cavities By FEM Based On Auto-meshing Technique

In this paper, edge-based finite element method (FEM) is combined with the auto-meshing technique in the analysis of electromagnetic problems related to complex cavities. Geometrical models are established by 3D CAD software and grids are generated automatically. A general interface is designed to exchange data between the CAD software and the FEM program. The complicity and inefficiency in traditional method are greatly decreased. And the interface separates the analysis by FEM from meshing which makes the FEM programs more general in its application to EM problems. Grids of high quality are generated by the arithmetic of the software, and results of computation become more accurate. Grid data is generated independently and the FEM programs are more easily to write. The main work included in the paper is as follows:Resonant frequencies of cavities with complicated shapes or complex materials filled are analyzed . The advantages of FEM in analyzing such problems are also mentioned , which are useful in the design of resonant cavities.The problems of waveguide discontinuities are analyzed by FEM combined with PML. The relationship between the S parameters and the amounts of dielectric cubes as well as the permittivity of the dielectric is also discussed. Some useful conclusions are also obtained.The radar cross section of grounded open cavities is computed by FEM combined with Boundary Integral Equation Method. The cavities filled with complex materials are also analyzed. Accurate results have been obtained. Advantages of this hybrid method in the analysis of such problems are pointed out.