Microstrip antennas with reduced surface-wave and lateral-wave excitation

Surface-wave and lateral-wave excitation from microstrip antennas results in undesirable edge diffraction of these fields from the edges of the substrate and ground plane, as well as undesirable mutual coupling between antenna elements. The edge diffraction of the surface waves and lateral waves may result in significant degradation of the radiation pattern, including frontside pattern rippling and backside fields. The mutual coupling due to the surface waves and lateral waves causes variations in the array scan impedance, including effects such as scan blindness.