Multilevel fast multipole method for higher order basis functions implemented in WIPL-D Pro

An overview of the variant of multilevel fast multipole method (MLFMM) applied in WIPL-D Pro 3D EM solver is given in this paper. MLFMM is applied to higher order basis functions (HOBFs), where grouping of basis functions is done in two levels, and far-field approximation is appropriately applied to distant groups. Maximally orthogonalized HOBFs are used because of their property of improving the conditioning of the method of moments (MoM) dense system of linear equations. Numerical results demonstrate the effects of the proposed approach in terms of dramatically reduced memory requirements (up to 100 times) compared to the full MoM simulation of electrically large structures.