A circularly polarized bi-directional surface wave antenna with low-profile

A surface wave antenna (SWA) with low profile and circular polarization is proposed. The proposed structure consisting two substrates: microstrip element on upper and feeding patch with ground plane on the lower. A microstrip line is radiating element with a length of approximately 2λ_g which can radiate circular polarization resulting in bi-directional beams along the longest part of the elements. The hook-shaped elements are added by connected to the ground plane to generate horizontal component of electrical field with 90-degree phase difference with the vertical components radiated by the microstrip element.