Trefftz-Discontinuous Galerkin and Finite Element Multi-Solver Technique for Modeling Time-Harmonic EM Problems With High-Conductivity Regions

This paper introduces a multi-solver technique to enhance the broadband performance of time-harmonic finite element solvers when solving electromagnetic problems with high-conductivity regions. The high-conductivity regions are modeled by the Trefftz-discontinuous Galerkin (TDG) formulation, whereas a tangential vector finite element (TVFE) formulation is used in the rest of the computational domain. The novel multi-solver technique couples the TVFE and TDG models by making use of Robin-type transmission conditions. The efficiency is shown by computing the broadband frequency sweep of the inductance of a two-wire transmission line; the necessary number of DoFs in the multi-solver case decreases significantly compared with the pure TVFE solution. The results of this problem also verify the new formulation and its implementation because the problem has an analytical solution.