A New Hybrid DGTD/FDTD Method for 3-D Multiscale Simulations

We present a simple scheme to hybridize the discontinuous Galerkin time-domain (DGTD) and the standard finite-difference time-domain (FDTD) methods for modeling multiscale structures, such as metasurface unit cells. We use an unstructured tetrahedral mesh to model curvilinear and sub-wavelength geo-metrical details in the DGTD region, while keeping a structured FDTD mesh for other areas, including the perfectly matched layer (PML). We present a simple scheme to connect the two regions in a stable manner. The proposed method leads to significant computational savings combined with high accuracy.