Abstract: A low profile patch antenna surface mounted to a metal base produces superior gain in horizontal directions. A dielectric spacer and matching circuit are sandwiched between a thin circular patch radiator and an opposite ground plate, with the matching circuit between the spacer and ground plate and electrically coupled to the ground plate and radiator. The matching circuit increases antenna efficiency and bandwidth by attaining the best possible energy transfer between a transceiver and the antenna, taking into account impedance mismatch, component losses, and losses in the antenna structure.