A Multi-Functional Reconfigurable Intelligent Surface with Integrated Sensing Capability

We present a Reconfigurable Intelligent Surface (RIS) topology for sensing and communication. The square unit cell of size lambda /2 consists of a 3x3 array of electrically small patches interconnected by switches operating at 10 GHz. Achieved wide phase response of this unit cell, enables precise control over the phase distribution of the surface. This characteristic enhances the surface's adaptability and improves its beam steering and beamforming capacities. Additionally, the design includes a sensing array to accurately calculate the direction of arrival of the incoming signals. However, for practical and cost-effective implementation, the number of switches can be minimized to a reduced 1-bit switch version. We demonstrate that an RIS designed with this unit cell can achieve multi-beam generation, diffuse scattering, and beam steering.