Integrated Sensing and Secure Communications via Pinching Antennas

Abstract

A pinching antenna (PA)-assisted integrated sensing and secure communication system is investigated. In this system, a uniform linear array (ULA) is employed at the base station (BS) for signal transmission, while PAs are utilized to capture sensing echoes. For the purpose of secure communications, artificial noise (AN) is injected into the transmitted signal to degrade the eavesdropping capability. A target localization Cramér-Rao bound (CRB) minimization problem is formulated under both secrecy rate requirement and total transmit power constraint. Specifically, an alternating optimization (AO) algorithm is developed to tackle this highly non-convex problem, where the beamforming and AN optimization at the BS are obtained via semidefinite relaxation (SDR) and successive convex approximation (SCA) while the PA deployment is solved through element-wise optimization. Numerical results demonstrate that the proposed scheme consistently improves sensing accuracy compared to conventional fixed antennas. Dynamically adapting PA positions mitigates severe path loss and achieves robust sensing coverage over a wide area. Furthermore, it provides additional sensing-side spatial degrees of freedom, which compensate for the localization degradation induced by stringent secrecy requirements.