Self-powered System-on-Chip for Substrate Computing and Ultrasonic Communications

Substrate computing refers to a paradigm where sensing, computing, communications, energy scavenging and energy storage functions are seamlessly integrated within a substrate. The substrate could be a part of an aircraft wing or a chassis of the car and the computing, communications and energy scavenging functions could be implemented using self-powered devices embedded inside the substrate. In this paper we present the design of a CMOS transceiver that could be used for through-substrate communications using ultrasonic pulses. The transceiver comprises of three piezoelectric interfaces, one of which is used for harvesting and regulating energy from mechanical vibrations in the substrate and the other two interfaces are used for transmitting and receiving ultrasonic pulses. We present measurement results using prototypes of the transceiver fabricated in a 0.5-mu m CMOS process integrated with piezoelectric transducers that are attached to a segment of an aluminum wing. The results demonstrate the energy-harvesting, regulation functionalities along with the bi-directional telemetry functions needed to implement a complete transceiver for substrate computing.