implantable medical devices

Ultrasonic power transfer has emerged as an efficient method for powering and communicating with small and deeply implanted medical devices. However, most work utilizing ultrasonically-coupled implants relies on non-hermetic polymeric encapsulation materials rather than conventional metal or ceramic packaging materials due to the inherent acoustic impedance mismatch of metals and ceramics. Here, we develop models of ultrasonic power transfer through metals, examining flexural and bulk mode propagation, to determine optimal package design for ultrasonic power transfer. We utilize these results to build millimeter-scale hybrid ceramic/metal packages, and perform benchtop demonstrations of ultrasonic powering and communication with a packaged electrophysiology sensor. read more