Low-Scattering and Dual-Polarized Reconfigurable Reflectarray Antenna Based on Absorptive and Active Coding Metasurfaces

This paper presents a low-scattering and dual-polarized reconfigurable reflectarray antenna (RRA). The whole reflectarray comprises an active coding metasurface cascaded with an absorptive metasurface above. Upon integration with p-i-n diodes, the unit cell achieves a reconfigurable reflected phase with a near 180° phase difference, leading to a high gain and ±60° beam scan performance. In addition, the multidrive modes of p-i-n diodes can realize absorption or scattering cancellation effects in the operating band of the RRA. The out-of-band scattering reduction performance is obtained owing to the absorptive metasurface’s absorption characteristics. As a demonstration, a low-scattering and dual-polarized RRA is fabricated. The proposed RRA can achieve a maximum 3-dB gain bandwidth of 21.6% and a maximum gain of 21.2 dBi with an aperture efficiency of 22.9% at 3.6 GHz. An overall scattering reduction band is observed from 1.5 to 6.34 GHz.