Capacitively Coupled Resonators for Misalignment-Tolerant Wireless Charging through Metallic Cases

This work proposes a novel wireless power transfer (WPT) system in the near-field region using open-ended helical resonators (OEHRs), taking advantage of their high quality factor characteristics. Instead of using the conventional approach of magnetic coupling between resonators, capacitive coupling is introduced between transmitter and receiver devices. This new configuration is designed to operate at the frequency of 6.78 MHz and is evaluated by measurement, simulation and equivalent circuit analysis. Furthermore, the proposed technology allows significant misalignment between transmitter and receiver structures, as well as enabling WPT to devices with a metallic case, which is not practical in conventional charging topologies.