RF telemetry powering and control of hermetically sealed integrated sensors and actuators

Abstract

An RF telemetry system for powering and control of microminiature integrated transducers packaged in a hermetically sealed custom-made glass capsule is described. A class-E power amplifier is utilized to energize and control a single-channel microstimulator for neuromuscular applications. The transmitter can deliver 1.5 W of power through a solenoid antenna using a 12-V rechargeable battery, while achieving efficiencies greater than 90%. The microstimulator antenna is a 1.5-mm-diameter, 4-5-mm-long ferrite-cored solenoid coil which can generate peak voltages of up to 50 V, and up to 50 mW of power. A custom-made glass capsule electrostatically bonded to the microstimulator's silicon carrier provides a hermetic package for the implant. Lead transfer into the sealed chamber is achieved using thin films of iridium insulated with low-pressure chemical vapor deposition (LPCVD) thin films. Helium leak tests on these structures show leak rates below 10/sup -9/ cm/sup 3//s.<>