Multi-Beam Reconfigurable Intelligent Surface with Adaptive Power Allocation for Multi-User Communication

Abstract

This work presents a multi-beam reconfigurable intelligent surface (RIS) capable of adaptive power allocation for multi-user wireless communication systems. Unlike conventional RIS configurations that generate beams with fixed amplitudes, the proposed design can dynamically adjust the power levels of individual beams depending on the requirements of users located at different spatial positions. The concept is validated for both single-user and multi-user scenarios by implementing RIS structures with different phase quantization levels (1-bit, 2-bit, and 3-bit). For the multi-beam case, two beams are formed toward arbitrary target directions at (θ1, φ1) = (30°, 45°) and (θ2, φ2)=(30°, 135°), and their power ratios are independently controlled to realize both equal and unequal power allocation schemes. The simulation results demonstrate that the proposed RIS architecture enables flexible multi-beam steering with tunable power distribution, thereby offering strong potential for next-generation multi-user MIMO and RIS-assisted wireless networks. © 2026 European Association of Antennas and Propagation.