A New Coupling Insensitive Nonlinear Capacitive Resonant Wireless Power Transfer Circuit

This paper presents a nonlinear capacitive WPT system that automatically compensate for the coupling variation between the transmitter and receiver in a capacitive wireless power transfer (WPT) system with no active circuitry. The system is capable of minimizing the output power variation at a fixed operating frequency of 13 MHz as the coupling distance varies. A constant output power is achieved over a wide range of coupling capacitance variation in comparison to the conventional capacitive wireless power transmission circuits. Such an approach is attractive for biomedical implants employing a capacitive WPT system.