Stable FEM-FDTD hybrid method for Maxwell's equations

A new hybrid scheme for Maxwell's equations, combining the Finite-Differenc e Time-Domain (FDTD) scheme and the Finite Element Method (FEM), is describ ed and tested. The hybrid method combines the efficiency of the FDTD with t he ability of the FEM to model complex geometry. The algorithm is completel y stable for the time steps up to the stability limit for the FDTD without added dissipation and produces no spurious solutions. Reflection coefficien ts of the interface between the FDTD scheme and the FEM are at most -45 dB when the grid has 18 cells per wavelength. (C) 2000 Elsevier Science B.V. A ll rights reserved.