2021/04/19 by Nikita Shanin, Shanin, Nikita, Laura Cottatellucci +3
Engineering · #Energy Harvesting in Wireless Networks #Wireless Power Transfer Systems #Antenna Design and Analysis
paper · pdf · doi:10.48550/arxiv.2104.09084
In this paper, we study multiple-input multiple-output (MIMO) wireless power\ntransfer (WPT) systems, where the energy harvester (EH) node is equipped with\nmultiple nonlinear rectennas. We characterize the optimal transmit strategy by\nthe optimal distribution of the transmit symbol vector that maximizes the\naverage harvested power at the EH subject to a constraint on the power budget\nof the transmitter. We show that the optimal transmit strategy employs scalar\nunit-norm input symbols with arbitrary phase and two beamforming vectors, which\nare determined as solutions of a non-convex optimization problem. To solve this\nproblem, we propose an iterative algorithm based on a two-dimensional grid\nsearch, semidefinite relaxation, and successive convex approximation. Our\nsimulation results reveal that the proposed MIMO WPT design significantly\noutperforms two baseline schemes based on a linear EH model and a single\nbeamforming vector, respectively. Finally, we show that the average harvested\npower grows linearly with the number of rectennas at the EH node and saturates\nfor a large number of TX antennas.\n