Backing of microstrip patch antennas fed by coplanar waveguides

Abstract

A microstrip antenna fed by a conductor-backed coplanar waveguide is demonstrated. The addition of a back-side metallic ground plane involves a possible leakage of the CPW mode into Parallel Plate Modes (PPMs) or the excitation of these PPMs by the back-radiation of the coupling slot. A theoretical model, based on the solution of coupled integral equations, is validated by experimental results. It is shown that the power leakage can be avoided by a proper choice of the substrate characteristics.