A Low-Frequency EFIE-MLFMA Solver Based on Approximate Diagonalization of Green’s Function

The low-frequency fast multipole algorithm (LFFMA) based on the approximate diagonalization of Green's function for the electric field integral equation (EFIE) is proposed for open and complex structures with high accuracy. Moreover, the multiresolution preconditioner is employed to the mixed potential form of EFIE with RWG basis functions for stability. Herein, a triangle-grouping scheme is adopted for the scalar potential so that the accuracy of the LFFMA can be guaranteed. Furthermore, the computational resources can be reduced largely since part of the radiation pattern of vector potential can share one of the scalar potentials by taking advantage of some mathematical deductions.