Dyadic Green’s Function of an Elementary Point Source above a Periodically-defected-grounded Dielectric Slab

A general formulation of Dyadic Green’s function for a point source above a two-dimensional periodic boundary is presented in spectral form. This formulation is simplified by considering only the zero term of the infinite Floquet modes. Then it is applied to obtain the Dyadic Green’s function of a printed source above a dielectric slab with periodically defected ground plane by using a generalized equivalent network of this defected ground plane. This equivalent network is obtained from the reflection coefficients of the defectedgrounded slab for different angles of incidence. This network includes equivalent impedances of the periodic surface for both TE and TM incident waves. In addition, it includes coupling impedance between the equivalent TE and TM networks. By determining the generalized equivalent network of the ground plane, the problem of the Green’s function can be formulated by coupled TE and TM transmission line networks.