1-bit Reconfigurable Intelligent Surface for Single-and Multi-beam Steering Applications

Abstract

In this paper, a reconfigurable intelligent surface (RIS) has been designed and developed for multi-beam steering applications in wireless communication. The unit cell is based on a varactor diode-embedded rectangular patch geometry, which exhibits a 1-bit quantization with a 90° phase shift between the states by precisely varying the diode voltage. A 30×30 elements array is implemented at 3.6 GHz, with a column-wise biasing circuit approach to optimize the complexity and power distribution. Overall, the RIS facilitates a dynamic beam steering over an angular range of ±60° with a gain improvement of 15±2.5 dBi. Furthermore, the geometry has been reconfigured to generate dual-beam radiation in specific directions, varied over a wide range. The structure has been fabricated and its measured responses validate the multibeam generation, thereby ensuring its applicability in high performance wireless systems. © 2025 Elsevier B.V., All rights reserved.