Zero-Power Ultrasonic Wakeup Receiver Based on MEMS Switches for Implantable Medical Devices

This article demonstrates, for the first time, a zero-power ultrasonic wakeup receiver for intra-body communication with Implantable Medical Devices (IMDs). The system is based on a 10 x 10 Piezoelectric Micromachined Ultrasonic Transducer (pMUT) array, a zero-power 500 nm gap MEMS plasmonic switch, a low-leakage CMOS load-switch, and an ad hoc sensing circuit. An ultrasonic signal of 10 mVpp is received by the pMUT array at a distance of 5 cm and brings the MEMS switch from the off-state (1 pA) to the on-state (20 mu A) when biased at 9.09 $V_{DC}$ . This small current then wakes up the load-switch (<10 nW when off), which powers up the sensing circuit to decode the pMUT signal. The system is demonstrated in a tissue phantom, making it ideal for intrabody communication.