Microstrip antennas fed by conductor backed coplanar waveguides

A microstrip antenna fed by a conductor backed coplanar waveguide is demonstrated. The addition of a back-side metallic ground plane involves a possible power leakage owing to the excitation of parallel plate modes (PPMs). 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 substrate characteristics