A PML-FDTD algorithm for general dispersive media in GPR and plasma applications

We present a 3D FDTD algorithm with the PML absorbing boundary condition for general inhomogeneous, dispersive, conductive media. The modified time-domain Maxwell's equations for dispersive media are expressed in terms of the coordinate stretching variables. A single formulation is developed to include recursive convolution and piecewise linear recursive convolution for arbitrary dispersive media. Several applications are demonstrated for subsurface radar detection (GPR-ground penetrating radar) of cylinders and a sphere buried in a dispersive half-space. The algorithm proposed is ideal for parallel computation since the same code is shared by both the interior computational region and the outer matched layers. Because of their generality, the algorithm and computer program developed can be used to model biological materials, artificial dielectrics, optical materials, and other dispersive media.