Metallic grating embedded in an anisotropic slab for realization of a reflectarray antenna

Abstract

A reflectarray antenna composed of a metallic grating sandwiched between two inhomogeneous anisotropic layers is proposed. The unit cell of this grounded structure contains two concentric square loops embedded in an anisotropic dielectric with an air hole drilled in its center. The phase diagram of the unit cell is calculated by a full-wave computational technique which uses the dyadic Green's function obtained by an equivalent transmission line (TL) model in the Fourier domain. The computed Green's function is used in an integral equation for the surface electric current on the metallic grating. The resulting integral equation is then solved using the Method of Moments (MoM) with sub-domain basis functions and Galerkin test functions. Finally, the entire antenna system, i.e., the designed reflectarray along with its feed antenna is analyzed using a full-wave EM solver. The numerical results show a gain of 26.78 dBi at 14.25 GHz for the designed 21cm × 21cm reflectarray.