2-bit Electrically Reconfigurable Reflectarray With Multi-Polarization Capability

In this paper, a low-complexity multi-polarization reconfigurable reflectarray antenna (RRA) with flexible 1- or 2-bit phase quantization is proposed, based on a PIN-tuned electrically rotatable element. The RRA element features an octagonal reflective patch integrated with four phase delay lines, each controlled by PIN diodes. By adjusting the ON/OFF states of the diodes, 1-bit phase reconfigurability for linearly polarized (LP) waves and 2-bit phase control for circularly polarized (CP) waves are achieved. To validate the concept, a <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">$16\times 16$ </tex-math></inline-formula>-element RRA prototype is fabricated and experimentally tested. An FPGA-based BCS is employed to enable dynamic electromagnetic functionality. Measurements confirm a ±60° beam-scanning capability. In the 1-bit LP-to-cross-LP mode, a 3-dB gain bandwidth of 10.6-12.8 GHz (~18.8%) is achieved, with a peak gain of 21.6 dBi and an aperture efficiency of 21.9%. For the 2-bit CP-to-co-CP mode, an AR <3 dB bandwidth of 21.3% and a 3-dB gain bandwidth of 18.4% are observed for both LHCP and RHCP. Peak gains of 23.8 dBic and 23.7 dBic are measured at 11.2 GHz, with aperture efficiencies of 37.1% and 36.3%, respectively. These results demonstrate the effectiveness of the proposed design, highlighting its strong potential for satellite communication and radar sensing systems where dual-mode reconfigurability is beneficial.