A Reconfigurable Intelligent Surface Using a 2-Bit Programmable Metasurface for Communications

Reconfigurable intelligent surfaces (RIS) have attracted significant interest as an enabling technology for future sixth-generation (6G) wireless communication networks. Programmable metasurfaces are a relatively low-cost and lowcomplexity architecture for realizing dynamic RIS arrays. This paper presents the design and simulation of a 128 element programmable metasurface antenna in a reflectarray configuration operating at 6 GHz with direct phase and frequency modulating capability for index modulation. This metasurface is a functional demonstration prototype and tile building block for larger RIS arrays. Specifically, we present full-wave simulation results of a meta-atom with 2-bit quantized phase shifts with an average reflection amplitude loss of 0.34 dB over all coding states. To the best of our knowledge, our 2-bit meta-atom design achieves lower reflection amplitude loss at the design frequency and is electrically thinner than existing designs. Additionally, we present full-wave simulation results of our 128 element RIS finite array performing beam steering and phase modulation.