Computation of the RCS of a complex BOR using FEM with coupled azimuth potentials and PML

An efficient finite element method (FEM) to compute scattering from a compl ex body of revolution (BOR) is discussed. The BOR is composed of perfect co nductor and impedance surfaces and arbitrary inhomogeneous materials. The F EM equations are developed using the coupled azimuth potential (CAP) formul ation. The FEM mesh is truncated with a perfectly matched layer (PML) in cy lindrical coordinates. The use of PML in cylindrical coordinates avoids the wasted computation which results from a spherical mesh boundary with an el ongated scatterer. The FEM equations are solved by ordering the unknowns wi th a reverse Cuthill-McKee algorithm and applying a banded-matrix solution algorithm. Numerical results are presented and compared to exact results an d measurements and to results from a previous FEM algorithm which uses edge -based vector basis functions to expand the transverse field components and node-based scalar basis functions to expand the angular component. Problem s associated with the CAP formulation are discussed and demonstrated throug h numerical examples.