Working frequency in wireless power transfer for implantable biomedical sensors

This paper presents a method to regulate the power, which transferred through an electromagnetic coupling link by adjusting the resonant operating frequency of its primary side. By receiving a feedback signal from the secondary side the needed power will be found and accordingly the resonance frequency will be adjusted. This is particularly useful when the wireless system is used to provide the needed power for implanted medical devices, where changing in distances between primary and secondary inductors is expected. The operating frequency is changed dynamically by changing the effective tuning capacitance in the primary side, based on the demanded power from feedback signals. A complete analysis of the proposed system has been undertaken, and experimental results have verified this method.