High-Gain and High-Selectivity Filtering Folded Reflectarray Antenna for Millimeter-Wave Broadband Applications Using Similar Elements

A high-gain and high-selectivity filtering folded reflectarray antenna (FFRA) for millimeter-wave broadband applications is proposed, utilizing similar elements. First, a frequency selective surface (FSS) is designed, featuring a wide passband and high frequency selectivity. Based on this FSS, a polarization selective surface (PSS) and a reflectarray are developed. The reflectarray achieves high frequency selectivity and polarization conversion within the range of 23.6 GHz to 31.6 GHz. The proposed FFRA consists of the PSS as a sub-reflector, the reflectarray as the main reflector, and a horn feed antenna. It has a 3 dB relative fractional bandwidth (RFBW) of 16.88 % (25.6 GHz to 30.3 GHz) and exhibits outstanding filtering characteristics, resulting from the combined effects of the PSS and the reflectarray. The simulated realized gain reaches 24.1 dBi at 28 GHz with an aperture efficiency of 17.6 %.