Experimental investigation of metasurface-based resonator for one-to-many wireless power transfer systems in the presence of foreign objects

The wireless charging of multiple devices simultaneously is on a high demand. Metasurface-based resonators with a uniform magnetic field distribution over a large area have been recently proposed as a transmitting resonator for one-to-many WPT systems. However, the problem of the influence of foreign objects on a one-to-many WPT system characteristics has not been deeply studied. Herein, we explore the influence of different foreign objects such as a metal screen, ferrites, coins, and a smartphone on the input impedance of the WPT system utilizing a metasurface-based resonator. We experimentally investigate the impact of foreign objects on the WPT system parameters and define the most destructive foreign objects. To avoid this parasitic impact, we modify the metasurface-based resonator design by shielding the magnetic field. We numerically demonstrate that the modified design does not provide any magnetic field beneath the metasurface-based resonator.