Optimal transmit beamforming for near-field integrated sensing and wireless power transfer systems

The integrated sensing and wireless power transfer (ISWPT) technology, in which the radar sensing and wireless power transfer functionalities are implemented using the same hardware platform, has been recently proposed. In this paper, we consider a near-field ISWPT system where one hybrid transmitter deploys extremely large-scale antenna arrays, and multiple energy receivers are located in the near-field region of the transmitter. Under such a new scenario, we study radar sensing and wireless power transfer performance trade-offs by optimizing the transmit beamforming vectors. In particular, we consider the transmit beampattern matching and max-min beampattern gain design metrics. For each radar performance metric, we aim to achieve the best performance of radar sensing, while guaranteeing the requirement of wireless power transfer. The corresponding beamforming design problems are non-convex, and the semi-definite relaxation (SDR) approach is applied to solve them globally optimally. Finally, numerical results verify the effectiveness of our proposed solutions. © 2020 Tsinghua University Press.