Decoupling in a joint communication and sensing system with metasurface

Abstract

Abstract The increasing demand for integrated communication and sensing has led to the development of Joint Communication and Sensing (JCAS) systems. However, strong self-interference (SI) between transmitting (TX) and receiving (RX) antennas remains a major obstacle, significantly degrading system performance in compact MIMO arrays. Traditional signal-processing-based cancellation methods face limitations in wideband scenarios due to high complexity and potential signal distortion. In this work, a novel metasurface-assisted decoupling structure is presented. The metasurface based on modified split-ring resonators (MSRRs) can suppress surface currents and reduce the coupling between TX and RX arrays. To further enhance isolation and reduce front-end self-interference in sensing-centric full-duplex JCAS, a multi-frequency null-space projection (NSP) beamforming algorithm is integrated with the antenna array design, forming a hardware–algorithm co-optimization framework. As proof of concept, a 2 $$\times$$ 2 patch antenna array incorporating the proposed metasurface operating in the 9–10 GHz band has been designed, fabricated, and characterized. The measurement results validate effectiveness. The findings suggest that the proposed decoupling approach offers a promising solution for enhancing electromagnetic isolation and overall system performance in next-generation JCAS applications such as intelligent transportation and indoor wireless sensing.