Microwave near-field capacitive coupling system for wireless powering appliations

This study presents the first reported near-field capacitive coupling system operating at 2.45 GHz for wireless charging mobile devices. The novel wireless powering system is constructed from a transmitting dock antenna and a receiving monopole antenna to demonstrate the compact and efficient characteristics. To enhance the capacitive coupling of wireless power transmission (WPT) system, the microstrip patch and the U-shape metal plate are employed in the dock antenna design. The equivalent circuits are established to obtain the amplitude and phase performances of the proposed WPT system. A good agreement among equivalent-circuit calculation, full-wave simulation, and measurement is observed, demonstrating the validity and versatility of the proposed modeling methodology and WPT configuration. Compared to the near-field capacitive coupling system using monopole and microstrip patch antennas, the presented WPT system exhibits high power transfer efficiency up to 71 %.