  We show that a capacitive wireless power transfer device can be designed as a
self-oscillating circuit using operational amplifiers. As the load and the
capacitive wireless channels are part of the feedback circuit of the
oscillator, the wireless power transfer can self-adjust to the optimal
condition under the change of the load resistance and the transfer distance. We
have theoretically analyzed and experimentally demonstrated the proposed
design. The results show that the operation is robust against changes of
various parameters, including the load resistance.
