A Fast FE-BI Method for the Computation of Monostatic Radar Cross Section

Finite element-boundary integral (FE-BI) is an efficient method to analyze electromagnetic scattering problems in an open region since it combines the advantages of the finite element method and integral equation method. The FE-BI method yields a partly sparse and partly dense matrix equation, which is often solved by iterative solvers. In this paper, a fast direct solver is presented to generate an efficient FE-BI method for computing the monostatic RCS. Based on the hierarchical matrix (H-matrix) algorithm, the proposed direct solver can reduce the computational complexity and memory requirements to be almost linear. For multiple excitation problems, one only needs to perform the H-matrix substitution while the H-LU decomposition only needs to be performed once. Numerical examples of the computation of the monostatic RCS for a scattering problem are presented.