Direct solution of electromagnetic scattering and radiation problems involving electrically large bodies using the multilevel Characteristic Basis Function Method (ML-CBFM)

In this paper, we show how the CBFM can be nested to generate multilevel characteristic basis functions on large blocks in a very efficient way. This technique, which is a rather natural extension to the conventional CBFM, results in a high compression rate and, therefore, the size of the final matrix in the method of moments (MoM) is reduced considerably. Once this reduced matrix has been factorized, multiple right hand side problems can be handled relatively efficiently by using a direct L-U decomposition of the compressed matrix.