A patch antenna with a frame radiating a circularly polarized, scanned beam

A circularly polarized (CP) radiation beam has been scanned using an array antenna with many radiation elements. In this paper, a single radiation element whose CP beam can be scanned is proposed. The radiation element is composed of a patch and its frame, each being excited by a coaxial line. The patch and frame are excited with the same amplitude and phase, and the radiation characteristics are examined using the FD-TD method. The CP radiation beam is formed in a direction tilted from the z-axis. Based on this result, the radiation characteristics when the beam is scanned is investigated. It is found that the elevation and azimuth angles of the beam direction can be controlled by changing the excitation amplitude and phase, respectively