A Polarization-Insensitive Reconfigurable Intelligent Surface for Beam Steering Applications

Abstract

With research being undertaken to develop supporting infrastructure for the 6G communication standard, the reconfigurable intelligent surfaces (RIS) have garnered substantive interest due to their ability to dynamically alter the propagation characteristics of the transmitted and received signals. One of the key applications of RIS is to provide dynamic beam steering, which ensures that the signal is only received by the intended receiver. This helps in providing transmission paths for the signal even in the presence of obstacles as well as in differentiating the legitimate users from an eavesdropper. The key concerns in designing such a surface are its polarization sensitivity and angular stability behavior with respect to the incident signal. Further, the tunable phase range is limited in most of the existing RIS geometries. In this work, we present a polarization-insensitive passive surface design, which achieves wide tunability of the reflection angle (in the range -160° to +160° by using varactor diodes and exhibits angular stability upto 60° for TE polarized signal. The full wave simulation results of the proposed design are presented, with the operating frequency centered around 3.1 GHz. The proposed work will be helpful in the realization of goals envisioned by the 6G standard and beyond.