Quarter wavelength resonators for use in wireless capacitive power transfer

Wireless capacitive power transfer is a growing research area that mainly focuses on non-radiating techniques. It has the potential to be highly efficient, low cost, and less susceptible to alignment issues. One major challenge hindering its widespread use is the high voltages found between the capacitive electrodes. Due to this, bipolar (dual, plus/minus electrode) techniques are predominant in literature, as unipolar (one electrode) techniques generally require even higher voltages for operation. Here we present the use of quarter wave resonators as one method to reduce electrode voltages while maintaining efficient energy transfer in a unipolar capacitive geometry. An accurate theoretical model is given based on standard circuit theory. Experimental verification of power transfer over a 5 m by 0.3 m surface is presented where various loads are placed on the system and changing phase parameters are measured.