Speeding-up the CBFM-MLFMA approach for scattering analysis of very large electromagnetic problems

A technique to reduce the CPU-time and computer memory spent in scattering electromagnetic problems when using the Characteristics Basis Function Method (CBFM) combined with the Multilevel Fast Multipole Algorithm (MLFMA) is presented. 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. The technique is based in retaining only the CBFs with a significant impressed field from external sources. Results show that the approach gives accurate results for both canonical and complex bodies.