Perfectly matched layers in three dimensions for the time-domain finite element method

The perfectly matched layer (PML) is very efficient and popular for grid truncation of open-region electromagnetic problems. In the context of the finite element method (FEM), the PML has been widely used for frequency-domain computations. On the other hand, the time-domain FEM formulation of the PML has been less investigated. Some of the first attempts involved approximations of the dispersive characteristics of the PML such that good absorption could only be achieved for a limited frequency band. We present a PML formulation for the time-domain FEM applied to three-dimensional problems. The proposed PML can be used for both scattered and total field formulations and we test it on radiating structures. Specifically, we demonstrate the accuracy and stability for the proposed algorithm given a short line current source.