Active RIS Assisted Near-Field Integrated Sensing and Wireless Power Transfer

This paper investigates a near-field integrated sensing and wireless power transfer (ISWPT) system, in which the transmitter with a large antenna array and an active reconfigurable intelligent surface (ARIS) join forces. Focusing on near-field transmission, we propose a joint optimization framework for ISWPT energy harvesting and sensing, which incorporates practical constraints including ARIS phase shifts, maximum amplification power budget, and per-antenna transmit power. To address the formulated non-convex problem, we propose an alternating optimization (AO) algorithm which employs successive convex approximation (SCA) to solve the decomposed subproblems. The simulation results demonstrate distinct advantages over benchmarks achieved by combining ARIS and the ISWPT system.