Time-Domain Field and Scattering Parameter Computation in Waveguide Structures by GPU-Accelerated Discontinuous-Galerkin Method

In this paper, we demonstrate the discontinuous Galerkin finite-element method (DG-FEM) used for the computation of electromagnetic fields in the interior of 3-D structures with open waveguide ports. This method is particularly applied to derive frequency-dependent scattering parameters. The method allows explicit formulations in time domain on unstructured meshes with high polynomial approximation order. Furthermore, it is well suited to be used in massively parallel organized computing environments. One necessary prerequisite for scattering parameter computations is the appropriate modeling of multimode broadband waveguide boundary conditions. Here we present a method of general applicability and its realization in the framework of DG-FEM. The entire procedure was implemented on low-cost graphic processing units. Two test examples are given, one of them of direct practical relevance in the field of particle accelerator design. The results are in excellent agreement with those of a commercially available frequency-domain finite-element method code.