An FDTD algorithm with perfectly matched layers for general dispersive media

A three-dimensional (3-D) finite-difference time-domain (FDTD) algorithm wi th perfectly matched layer (PML) absorbing boundary condition (ABC) is pres ented for general inhomogeneous, dispersive, conductive media. The modified time-domain Maxwell's equations for dispersive media are expressed in term s of coordinate-stretching variables. We extend the recursive convolution ( RC) and piecewise linear recursive convolution (PLRC) approaches to arbitra ry dispersive media in a more general form. The algorithm is tested for hom ogeneous and inhomogeneous media with three typical kinds of dispersive med ia, i.e., Lorentz medium, unmagnetized plasma, and Debye medium. Excellent agreement between the FDTD results and analytical solutions is obtained for all testing cases with both RC and PLRC approaches. We demonstrate the app lications of the algorithm with several examples in subsurface radar detect ion of mine-like objects, cylinders, and spheres buried in a dispersive hal f-space and the mapping of a curved interface. Because of their generality, the algorithm and computer program can be used to model biological materia ls, artificial dielectrics, optical materials, and other dispersive media.