Design of Single-Layer Circularly Polarized Filtering Reflectarray Antenna

To the authors' knowledge, very few filtering reflectarray antennas have ever been reported until now. A single-layer circularly polarized filtering reflectarray antenna (CPFRA) is presented in this paper. The phase compensation element of proposed CPFRA design is adopted with a novel high frequency-selective polarization rotation reflective surface (PRRS). The phase compensation of proposed CPFRA is realized through rotating the PRRS element around with its center under illumination of circularly polarized feed antenna. The novel frequency-selective bandpass PRRS periodic element is mainly composed of a rectangular ring and the metallic ground. Especially, through the suitable coupling effect of the dual-mode resonance of the rectangular ring, a polarization conversion reflection zero can be easily introduced at the upper or lower stopband of the PRRS design. Moreover, the novel PRRS has the good merits of flexibly adjusting the location of polarization conversion reflection zero. For the verification of the proposed CPFRA design method, a prototype antenna has been presented as an example with its center frequency of 30GHz. The simulated results show that the antenna has good filtering performance, which verifies the proposed CPFRA design method.