Joint Active and Passive Beamforming Design for Secure RIS-Aided ISAC System

This letter studies the reconfigurable intelligent surface (RIS)-aided integrated sensing and communication (ISAC) system while considering physical layer security (PLS). In this model, communication users and targets are located in conventionally non-line-of-sight (NLoS) covered areas of the base station (BS). The RIS is deployed to create virtual line-of-sight (LoS) links. Our aim is to maximize the minimum sensing performance through beamforming design under both secrecy rate and transmit power constraints. To solve this problem, an alternating optimization (AO) framework is proposed, and a corresponding complexity analysis is provided. Numerical results demonstrate that our proposed design yields enhanced sensing performance compared to both random phase and separate beamforming schemes.