A Hybrid Fem/Bem/Wtm Approach for Fast Solution of Scattering From Cylindrical Scatterers With Arbitrary Cross Sections

Abstract

A hybrid approach, combining the finite element method (FEM), boundary element method (BEM) and wavelet transform method (WTM), called FEM/BEM/WTM, is proposed for efficient solution of scattering from cylindrical scatterers of arbitrary cross sections. The hybrid technique uses the FEM to formulate the fields within a chosen fictitious boundary enclosing the considered scatterers and establish a relationship with those on the fictitious boundary. The fields outside the fictitious boundary are formulated by the integral equation method involving an integral expression of the fields over the fictitious boundary. Two fast-solving ways based on the WTM are presented. The use of the proposed hybrid technique always results in sparse moment matrices which can be efficiently solved by a sparse solver. Uniting the advantages of the FEM, BEM and WTM, the hybrid technique is able to effectively handle large-size unbounded problems in which arbitrary complex inhomogeneities are involved. Numerical results are given to demonstrate the merits of the hybrid technique.