The Free-range Resonant Electrical Energy Delivery (FREE-D) wireless power system uses magnetically coupled resonators to efficiently transfer power across meter distances to an artificial heart, specifically a ventricular assist device (VAD) implanted in the human body. Previously, artificial heart pumps recieved power from a wire through the chest, limiting patient quality of life. The FREE-D system will cut down on cardiac patients' dangerous infections and improve quality of life.

In the FREE-D system, transmit and receive resonators are essentially coils of wire that are tuned to resonate at a specific frequency. The resonator size and shape can be modified to accommodate application specifications, such as room size and patient body geometry. Additionally, an adaptive frequency tracking method can be implemented to achieve maximum power transfer efficiency – upwards of 70% – for nearly any angular orientation over a range of separation distances.