1-bit Reconfigurable Reflectarray Design With Low Power Consumption Based on Resistance-Insensitive Unit Cells

In this article, a 1-bit reconfigurable reflectarray (RRA) based on resistance-insensitive unit cells (RIUCs) is proposed for low power consumption reconfigurable intelligent surface (RIS) applications. By tactfully placing a p-i-n diode in the middle of an H-slotted patch, 1-bit phase quantization is achieved, which is insensitive to the equivalent resistance of the p-i-n diode. The phase difference between on and off states remains $180^{\circ }~\pm ~20^{\circ }$ from 5.09 to 5.62 GHz. The RIUC has stable reflection loss in the scene of high resistance of the p-i-n diode in on state, because the current flowing through the p-i-n diode is very small, compared to the total current of the RIUC. This property is utilized to reduce the forward biasing current, thus achieving low power consumption. A $16\times 16$ RRA prototype is fabricated. The 2-D beam-scanning performance with a peak gain of 22.10 dBi is realized, corresponding to an aperture efficiency of 24.9%. The measured 1-dB gain-bandwidth is 9.16%. An extremely low power consumption of 1.64 mW for the proposed RRA is realized at the cost of less than 0.7-dB gain drop. Moreover, the proposed RIUC is further modified to operate well in the millimeter-wave frequency band.