Battery-less microdevices for Body Sensor/Actuator networks

In this paper we discuss a novel approach to delivering wireless power to remote microdevices within Body Sensor/Actuator Networks. With higher energy budgets such devices could extent their functionality from purely diagnostic to therapeutic, and perform such operations as implant mechanical adjustment, drug release, microsurgery, or control of microfluidic valves and pumps. The method is based on ultrasonic power delivery, the novelty being that actuation is powered by ultrasound directly rather than via electrical form. The paper focuses on the main part of the system — a coupled mechanical oscillator driven by acoustic waves — and presents the first experimental results. Several issues related to the biomedical application of the system are also discussed. These include estimating acoustic power levels to avoid adverse bioeffects and tissue damage, as well as studying how the source-receiver misalignment (lateral and angular) affects the system performance.