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