An improved incident-wave formulation for broadband electromagnetic scattering by discontinuous Galerkin time-domain method

In this article, an incident-wave directly loaded (IWDL) method based on the discontinuous Galerkin time-domain (DGTD) method for broadband electromagnetic (EM) scattering problems is proposed. Each element of DGTD has a set of unknowns. Therefore, it allows us to put the incident surface and scatterer boundary surface together, using the interior unknowns of the surface to impress the incident wave and using the exterior unknowns for fields extrapolation on the same surface. Compared with the traditional total-and scattered-field decomposition (TSFD) method, the computational domain in IWDL is reduced from four regions to three regions. The surfaces needed to be dealt with are reduced from three surfaces to only one surface. Therefore, IWDL can effectively reduce the number of the degrees of freedom (DoF) and simplify the EM scattering modeling. In addition, the accuracy has been greatly improved because of the elimination of the dispersion error, which is associated with the propagation of both the incident field from the incident surface to the scatterer and the scattered field from the scatterer to the surface used for field extrapolation. The correctness and efficiency of this method are verified by some numerical examples involving EM scattering problems.