Phase-coded Magnetic Metasurfaces for Interference Free Multi-receiver Wireless Power Transfer System

In this study, the performance of a resonant inductive wireless power transfer system has been enhanced by introducing a phase-coded low-frequency magnetic metasurface in a multi-receiver arrangement. The magnetic metasurface, composed of an array of spirals cylindrically located in 3D space and loaded with a suitable set of capacitors, is able to both control the amplitude and phase of the magnetic field transferred to the receivers. By carrying out accurate full-wave simulations, we proved that it is possible to obtain two spatial regions characterized by a magnetic field distribution constant in amplitude and 180° out-of-phase even by adopting a single driving coil. Thus, two different receivers can be positioned in the aforementioned regions, obtaining two correspondingly out-of phase useful currents. In this way, power transfer can be combined with interference-free telemetry for both the receivers, opening the way for a new generation of wireless power transfer systems.