A Higher-Order Local Interpolation/Anterpolation Scheme of MLFMA for Computing Electromagnetic Scattering by Low RCS Objects

Realistic electromagnetic (EM) scattering problems often consist targets or structures aiming to reduce radar cross section (RCS) at some angle ranges, generating a challenge for the interpolation/anterpolation schemes of MLFMA. In this paper, we demonstrate that for a specially designed low RCS object, traditional local interpolation schemes using 4×4 samples cannot guarantee satisfactory accuracy. To remedy this, a higher-order Lagrangian interpolation scheme is proposed, whose performance is verified by numerical results. The proposed scheme has been used to calculate real-life EM scattering problem with coated cavities, nonconformal mesh grids and unknowns exceeding 48 million.