Parity-Time Symmetric Capacitive Wireless Power Transfer with Extended Transfer Distance

Abstract

Despite increasing popularity of capacitive wireless power transfer as a complementary technique to its inductive counterpart, the capacitive system entails a major performance bottleneck in terms of robustness of power transfer level over separating distance due to inherently low nature of electric couplings as compared to magnetic fields. This work develops an enhanced capacitive wireless power transfer system by means of incorporating the parity-time symmetry, with the capability to maintain transferred power over a significantly extended distance. General theoretical analysis is derived for parity-time symmetric capacitive power transfer based on both series and parallel coupled resonators. A practical parity-time symmetric capacitive system with a 10-W power delivery was designed and simulated. Extensive simulation using practical components indicates more than twenty-fold increase in the transfer distance than its conventional non-parity-time-symmetric capacitive counterpart, with an efficiency over 90%.