RCS reduction technique for reflectarray antennas

The performance of a concentric ring reflectarray element backed either by a solid metal ground plane or a frequency-selective surface is compared. Simulated and measured results show that the ‘in-band’ reflection phase response of the two structures is similar; however, the periodic surface reduces the ‘out-of-band’ reflectivity of the antenna by more than 4 dB, thereby decreasing its RCS profile to these signals.