Hierarchical scheme for the application of the Characteristic Basis Function Method based on a multilevel approach

We have presented herein a procedure for the generation of high-level Characteristic Basis Functions by using a chained SVD-based technique. The proposed method reduces the overall number of basis functions to be considered for the generation of the reduced matrix and, furthermore, it is very well suited for combining it with a CBFM-MLFMA implementation, because of the similarities between the hierarchical aggregation of CBFs and the expansion in terms of multipoles for several levels.