Optimal Terminations for a Single-Input Multiple-Output Resonant Inductive WPT Link

This paper analyzes a resonant inductive wireless power transfer link using a single transmitter and multiple receivers. The link is described as an (N+1)-port network and the problem of efficiency maximization is formulated as a generalized eigenvalue problem. It is shown that the desired solution can be derived through simple algebraic operations on the impedance matrix of the link. The analytical expressions of the loads and the generator impedances that maximize the efficiency are derived and discussed. It is demonstrated that the maximum realizable efficiency of the link does not depend on the coupling among the receivers that can be always compensated. Circuital simulation results validating the presented theory are reported and discussed.