  A parallel dispersive finite-difference time-domain (FDTD) method for the
modeling of three-dimensional (3-D) electromagnetic cloaking structures is
presented in this paper. The permittivity and permeability of the cloak are
mapped to the Drude dispersion model and taken into account in FDTD simulations
using an auxiliary differential equation (ADE) method. It is shown that the
correction of numerical material parameters and the slow switching-on of source
are necessary to ensure stable and convergent single-frequency simulations.
Numerical results from wideband simulations demonstrate that waves passing
through a three-dimensional cloak experience considerable delay comparing with
the free space propagations, as well as pulse broadening and blue-shift
effects.
