Study of efficient FEM-based iteration method for open region problem and its application to scattering from a three-dimensional cavity-backed aperture

An efficient iterative finite element method for solving a three-dimensiona l scattering problem is proposed. With only a small number or meshes around a three-dimensional scatterer, the typical finite element method is shown to give an exact solution by carrying out several iterative updates of the radiation-type boundary conditions. The proposed method is used to analyse the scattering from a three-dimensional cavity-backed aperture, and the res ults obtained show good agreement with data obtained using another method.