Design of 1-Bit Digital Reconfigurable Reflective Metasurface for Beam- Scanning

A 1-bit digital reconfigurable reflective metasurface (RRM) with 20 x 20 cells is presented, fabricated and measured for beam-scanning performance in this paper. The cell is designed with a single layer structure and one varactor diode, controlled electronically. The cell's phase compensation is over 180 degrees between 3 GHz and 4 GHz and the two states with 180 degrees phase difference are selected as coding "0" and coding "1". By the fuzzy quantification theory, all the elements on the RRM are set to be coding "0" or coding "1" according to the phase compensation calculated by MATLAB. Furthermore, by changing the coding of the RRM, it can achieve beam-scanning. The simulation results show that the beam-scanning range is over +/- 60 degrees. The RRM prototype is fabricated and experimentally tested for principle. The gain of the RRM is 18 dB and the 3 dB bandwidth is about 16.6%. The 1-bit digital RRM is preferred in practical implementations due to less error and much easier bias voltage control. The proposed RRM successfully balances the performance and system complexity, especially in the large-scale antenna designs. The experimental and simulated results are in good agreement to prove the correctness and feasibility of the design of the 1-bit digital RRM.