Application of FEM-BIE for scattering from dielectric objects buried under a rough surface

This paper presents a hybrid method combining the finite element method (FEM) with the boundary integral equation (BIE) for two dimensional (2D) scattering from dielectric objects buried under the rough surface. In the hybrid method, one boundary integral equation is adopt to depict the scattering above the rough surface on the basis of Green´s function. Based on the domain decomposition technique, the computational region below the rough ground is divided into multiple isolated interior regions containing each object and the exterior region. Finite element formulations are only applied inside interior regions to derive a set of linear systems, and another boundary integral formula is developed below the rough surface which also act as the boundary constraints of the FEM regions. Compared with traditional FEM based on perfectly matched layer (PML), the hybrid technique presented here is highly efficient in terms of computational memory, time, and versatility.