A fast higher-order time-domain finite element-boundary integral method for 3-D electromagnetic scattering analysis

We present a hybrid time-domain finite element-boundary integral (FE-BI) method for analyzing 3D electromagnetic open-region transient scattering phenomena. This method has three unique features. The first is the hybridization scheme that combines the FE and BI representations of the fields. Instead of following the standard hybridization scheme used in the frequency domain, we propose a novel scheme that preserves the sparsity of the finite element matrix and that yields solutions free of spurious modes associated with interior BI resonances. The second feature is the use of a fast algorithm, the multilevel plane-wave time-domain (PWTD) method, for evaluating the BI. Invoking this scheme greatly reduces the computational expense when an object of large electrical dimensions is considered. Third, the FE component of the solver employs curvilinear tetrahedral elements to precisely model the scatterer's geometry and higher-order vector basis functions to accurately represent the fields.