High power transfer density and high efficiency 100 MHz capacitive wireless power transfer system

This paper introduces a very high frequency (VHF) capacitive wireless power transfer architecture capable of achieving very high power transfer densities and high efficiencies. High power density is achieved using an operating frequency of 100 MHz and through appropriate design of matching networks. High efficiency is achieved using a custom designed half-bridge GaN chip with integrated gate drivers. To validate performance of the proposed architecture, a prototype capacitive wireless power transfer system is built and tested. Experimental results demonstrate that the system transfers 2.5 W of power across a 1 pF capacitive interface at a very high power transfer density of 1.1 W/mm², at close to 90% efficiency.