An adaptive technique to improve wireless power transfer for consumer electronics

This paper presents an adaptive technique to enhance the efficiency of magnetic resonance based wireless power transfer system for future portable consumer electronics. In order to transfer energy to mobile devices, asymmetric coupling resonators with larger sizes of coils in a transmitter than those in a receiver are exploited. By changing a coupling coefficient between coils only in the transmitting side, the system performance increases significantly. An experiment setup has been developed, and the S₂₁ parameter has been measured showing 3.3 dB improvement of system using the adaptive technique at a distance of 65 cm. An important finding is that the technique is also effective in case of multiple receiving coils. The measured performance was improved by roughly 1 dB with the use of the adaptive technique.