A 2-bit Reconfigurable Intelligent Surface Based on Open-end Transmission Lines

In this paper, a $4 \times 4$ 2-bit Reconfigurable Intelligent Surface(RIS) based on a microstrip patch antenna array and a switched phase-shift network(SPSN) is proposed. The RIS is designed, simulated, fabricated and measured. The measured results are consistent with the simulation results. The experimental results show that the antenna array operates in $6.6 \sim 6.8 \mathrm{GHz}$ band with good broadside radiation characteristics. The switched phase-shift network is capable of realizing tunable reflective phase shift from 0 degree to 270 degrees with steps of 90 degrees.