The objective of this paper is to present a numerical technique for the analysis of printed circuits and antennas using the grounded dielectric slab Green's functions. For the dynamic case, the Green's functions are quite complicated and require the numerical computation of certain semi-infinite integrals commonly known as the Sommerfeld integrals. In this paper certain approximations have been made resulting in much simpler expressions for the near field Green's functions. Finally, numerical examples are presented in order to validate the technique.