A Phase Synthesis Method for Mechanical Beam Scanning of Reflectarray Antennas

In this letter, a phase synthesis method for mechanical beam scanning based on the feed displacement technique (FDT) is proposed for reflectarray antennas. To verify the correctness of the optimization method, the high-performance magnetic enhanced reflectarray antenna (MERA) element is used, which has a cross-polarization level consistently less than −30 dB in the range of 9.2 GHz to 9.8 GHz and the reflection phase remains essentially constant in the range of 0° to 45° incidence angle. Using this element, an FDT-based MERA prototype was designed and fabricated. The prototype was able to maintain a gain variation of less than 1 dB within a beam-scanning range of ±40° and no more than 3 dB over ±55°, achieving a maximum aperture efficiency of 64.85% in its operating band. The proposed method is applicable to simplify the beam-scanning system and improve the scanning performance of reflectarray antennas.