Efficient Interaction Methodologies for Simulating the Scattering from Electrically Large Objects and Scenes

In this proposal RMA describes two fresh new approaches, based on the Characteristic Basis Function Method (CBFM), as a way to handle the radiation and scattering problems of interest in this project. We offer two versions of the CBFM, one for the frequency and the other for the time domain, based on the MoM and FDTD formulations. In contrast to the Fast Multipole Method (FMM), the CBMOM solves large problem without resorting to iteration and, hence, does not suffer from convergence problems that often plague the iteration method, even when dealing with resonant structures that render the problem ill-conditioned; hence, unlike the FMM, which relies upon an iterative procedure, it is well-suited for handling multi-scale problems. Furthermore, the CBMOM handles multiple incidence angles and frequencies far more efficiently than do the iterative techniques such as the FMM. The time domain version of the CBFM, can handle complex inhomogeneous materials, including metamaterials. Incidentally, both the CBMOM and CBFDTD codes are based on algorithms that are highly parallel. Another unique feature of the CBMOM and CBFDTD algorithms is that they are both physics-based rather than being purely numerical.