A Memory-Efficient Implementation of Perfectly Matched Layer With Smoothly Varying Coefficients in Discontinuous Galerkin Time-Domain Method

Wrapping a computation domain with perfectly matched layer (PML) is one of the most effective methods imitating/approximating radiation boundary condition in Maxwell and wave equation solvers. Many PML implementations often use smoothly-increasing attenuation coefficient to increase absorption for given thickness, and, at same time, reduce numerical reflection from interface between PML. In discontinuous Galerkin time-domain (DGTD) methods, using that varies within mesh element requires different mass matrix be stored every therefore significantly increases memory footprint. this work, bottleneck addressed by applying weight-adjusted approximation these matrices. The resulting DGTD scheme has advantages as stores individual matrices, namely higher accuracy (due reduced reflection) increased meshing flexibility (since does not have defined layer) but it less memory.