Unsplit-field FDTD implementations of the PML using DSP algorithms

A simple algorithm is presented for the finite difference time domain (FDTD) implementation of the stretched coordinate perfectly matched layer (PML) formulations. The algorithm is based on incorporating the digital signal processing (DSP) algorithms developed for digital filters into the PML formulations. The advantage of this method is that it allows direct FDTD implementation of Maxwell´s equations in the PML region without the need for splitting the field components. In addition, the formulations are implemented using D and B fields, rather than the conventional E and H. This allows the PML to be independent from the material properties of the FDTD computational domains. Numerical tests are carried out in two dimensions to validate the proposed formulations.