Ultrasonic Wake-Up With Precharged Transducers

Abstract

We present an ultralow-power millimeter-sized ultrasonic wake-up receiver (WuRx) that uses precharged ultra- sonic transducers to wirelessly receive wake-up signatures. Our WuRx takes advantage of the low carrier frequency afforded by the low speed of sound to achieve high impedance, and thus high sensitivity, operation in a millimeter-sized form fac- tor. We discuss the system-level considerations that arise from the use of ultrasound as a mode of signature transmission, including the choice of