Powering Implantable Telemetry Devices from Localized Magnetic Fields

This paper presents a novel method of inductively powering an implantable telemetry device over a large area. The system is based around an array of individually tuned series resonant circuits distributed across a charging pad. By varying the frequency of the driving voltage, the location of the charging field is changed. Presented are a method of controlling the resonant frequency and techniques for determining the geometry of the charging pad. Results from a nine coil system operating between 97 kHz and 209 kHz are given which can deliver 100 mW to an implanted telemeter at a height of 5 cm above the charging pad.