AN EFFICIENT HYBRID-SCHEME COMBINING THE CHARACTERISTIC BASIS FUNCTION METHOD AND THE MULTILEVEL FAST MULTIPOLE ALGORITHM FOR SOLVING BISTATIC RCS AND RADIATION PROBLEMS

A numerically e-cient approach for the rigorous compu- tation of bi-static scattering and radiation problems is presented. The approach is based on an improvement of a previous method scheme that combines the Characteristic Basis Function Method (CBFM) and the Multilevel Fast Multipole Algorithm (MLFMA). The approach com- bines Characteristic Basis Functions (CBFS) and subdomains func- tions for reducing the CPU time in the pre-process and in the solving iterative process for simple or multiple excitations. It is intended for use in very large cases where an iterative solution process cannot be avoided, even considering the matrix size reduction achieved by the CBFM. This reduction is particularly important for solving radiation or bistatic problems in which an integral equation is solved once.