A direct time-domain FDTD near-field-to-far-field transform in the presence of an infinite grounded dielectric slab

A direct time-domain near-field-to-far-field transform (NFFFT) is developed that is applicable to the finite-difference time-domain analysis of radiation in the presence of a non-dispersive, infinite, grounded dielectric slab. With minor modification and/or simplification, the results can also be applied to the dielectric half-space and the infinite ungrounded dielectric slab. A few time-domain radiation examples involving microstrip transmission lines are used to illustrate the method. Index Terms--Finite-difference time-domain (FDTD), microstrip, nonhomogeneons media.