Stable FEM-FDTD hybrid method for Maxwellʹs equations Original Research Article

A new hybrid scheme for Maxwellʹs equations, combining the Finite-Difference Time-Domain (FDTD) scheme and the Finite Element Method (FEM), is described and tested. The hybrid method combines the efficiency of the FDTD with the ability of the FEM to model complex geometry. The algorithm is completely stable for the time steps up to the stability limit for the FDTD without added dissipation and produces no spurious solutions. Reflection coefficients of the interface between the FDTD scheme and the FEM are at most −45 dB when the grid has 18 cells per wavelength.