A Metal-Only Folded Reflectarray Utilizing Modified Split Ring Slot Elements

A metal-only folded reflectarray employing modified split ring slot elements is proposed. The reflectarray comprises a polarization-conversion reflectarray integrated with a feed horn and an upper polarizer. The element enables continuous 360° phase coverage by varying the opening angle and mirroring its structure. Waves are reflected twice between the upper and lower layers of the folded array, reducing the profile by 1/2. A 625-element array has been designed and manufactured. The testing results demonstrate that the reflectarray exhibits a peak gain of 29.4 dBi with maximum aperture efficiency of 52.1%. Furthermore, the measured 3-dB gain bandwidth is 14%.