Radiation characteristics of a patch antenna on a thin PBG substrate

A periodically loaded substrate is employed to reduce excitation of surface waves by a patch antenna. The computed dispersion diagram of the substrates shows that surface wave propagation is forbidden along specific directions. By properly orienting the patch antenna on the substrate, this can result in good improvement of antenna performance. In agreement with the expected result, the measured radiation pattern shows a 10 dB reduction in the side lobes associated with power launched from surface waves.