Wireless Power Transmission for Implantable Medical Devices Using Focused Ultrasound and a Miniaturized 1-3 Piezoelectric Composite Receiving Transducer

Wireless power transmission (WPT) using ultrasound is a promising way for wirelessly recharging implantable medical devices (IMDs). However, the transmitted power using ultrasound so far is insufficient for driving the existing IMDs. Moreover, the size of the receiving transducer is larger, which is not suitable for implantation. To increase the output power and reduce the size of the implantable receiver, this article presents a method of combining focused ultrasound with a miniaturized 1-3 piezoelectric composite receiving transducer to produce higher electrical power. An analytical fluid–structure interaction model is constructed to fully understand the operating mechanism of the receiving transducer under ultrasonic force. In our experiments, a miniaturized 1-3 piezoelectric composite receiving transducer with a diameter of 3.7 mm was used. The output power generated from the receiving transducer reached 60 mW at a distance of 150 mm.
In vitro
and
in vivo
animal experiments proved that the miniaturized transducer could successfully receive focused ultrasonic energy and convert it to electrical power. The method presented and the electrical power that we obtained can provide a valuable reference for wirelessly charging of IMDs.