Design of a 2-bit Dual-Polarized Reconfigurable Reflectarray with High Aperture Efficiency

In this article, a dual-polarized 2-bit electronically reconfigurable reflectarray (RRA) is proposed for 5G beam scanning applications. By introducing two parallel transmission lines and a T-junction, only two p-i-n diodes are used to generate 2-bit phase quantization is analyzed and verified. Based on this concept, a novel 2-bit dual-polarized RRA element is presented that makes use of an aperture-coupled patch and microstrip delay lines behind its ground plane. Only two p-i-n diodes are loaded on each delay line to realize the 2-bit phase quantization. Two orthogonal linear polarizations are independently controlled by deploying two perpendicular coupling slots and two delay lines. A $16\times16$ RRA prototype is fabricated and tested at 3.6 GHz. The measurement and simulation results show good agreement. Both polarizations can provide a ±60° 2-D beam scanning range with a maximum scanning gain drop of 2.75 dB. The maximum measured gain is 23.11 dBi, which corresponds to an aperture efficiency of 40.56%. A 1-dB measured gain bandwidth of 8.06% is also achieved.