A Low-Profile 2-D Beam-Scanning Circularly Polarized Antenna Combining Reflectarray and Transmitarray

Traditional Risley-prism antennas are usually based on planar transmitarray antennas, utilizing two or three layers of rotatable transmitarrays to achieve 2-D beam scanning. To reduce the number of transmitarray layers, a novel Risley-prism antenna that combines a reflectarray and a transmitarray is proposed. By simultaneously controlling the transmission phase and polarization state of the waves, the profile can be reduced to only half that of a reflectarray. Additionally, by rotating both the transmitarray and the reflectarray, the circularly polarized beam-scanning capability in a 2-D plane is achieved. Moreover, the proposed antenna features a wide scanning angle, low profile, and compact structure, making it an excellent candidate for wireless communication systems.