Optimization of Near Field Coupling for Efficient Power Transfer Utilizing Multiple Coupling Structures

Abstract

A rise in the need for dynamic energy allocation has been associated with the saturation of available portable wireless electronic devices. Currently, the methods for transmitting this energy efficiently have been limited to a number of options, including near field resonant magnetic coupling. Previous research with mid-range (dâ 4r) wireless power transfer has resulted in coupling efficiencies of close to 40%. In order to increase efficiency in transfer a more directive transmission system was developed using a phased array. Coupling networks were used to shift the resonance of the coupling device, leading to a tightly coupled network by array phasing. Coupling networks for the phased array were optimized using a hybrid combination of a full wave Method of Moments simulation with circuit simulation. Results were validated in a full wave simulator, and field results were shown during resonance. S-parameter results show simulated transfer efficiencies of 70% (-1.5dB) for a phased array structure and 62.3% (-2.4dB) for a single feed structure. Single feed prototyping S-parameter results show coupling efficiencies of 25% (-5.9dB). All coupling measurements are at a distance 4r with reference to the largest transmitting coupler.