Hybrid finite element-boundary integral method accelerated by the NSPW-MLFMA

This article presents a hybrid finite element-boundary integral equation (FE-BIE) method where the boundary integral interactions containing the 2D Green´s kernel function are accelerated by the nondirective stable plane wave multilevel fast multipole algorithm (NSPW-MLFMA). This hybrid method enables the fast simulation of very large scale scattering problems with multiple homogeneous and inhomogeneous dielectrics and perfectly electric conducting (PEC) objects. The new hybrid technique with FMM acceleration applies for both high frequency as low frequency as long as the finite element mesh is sufficiently fine to contain the numerical dispersion within the desired accuracy. The hybrid formulation is outlined, and its validity is demonstrated by means of a 2D scattering problem.