Continuous Aperture Array-Based ISAC Systems: How to Achieve Pareto Optimality?

Enabled by metamaterials, continuous aperture array (CAPA) has been proven to play a crucial role in communication performance enhancement, while its potentials in integrated sensing and communication (ISAC) systems have not been investigated. This paper investigates the performance analysis and optimization of CAPA-based ISAC systems for simultaneous user communication and target sensing. To be specific, communication and sensing rates are evaluated based on electromagnetic channels and a Pareto-optimal problem is formulated for beamforming optimization. Closed-form solutions to CAPA-oriented beamforming are derived under communication-, sensing-, and Pareto-optimal cases, and the attainable ISAC rate region is obtained. Numerical results verify that CAPA-based systems can achieve the ultimate sensing and communication performance of spatially discrete array (SPDA)-based systems and significantly expand the ISAC rate region for Pareto optimality.