Professors Steven Bowers, Ben Calhoun and Scott Barker at UVa and Prof. Songbin Gong at the University of Illinois at Urbana-Champaign are using multifunctional integration to address a fundamental obstacle to the realization of systems like the Internet of Things — power usage. The thousands of tiny sensor nodes distributed throughout the environment or embedded in physical objects must use power extremely sparingly if the system is to function for any length of time. Bowers team is focusing on minimizing the energy drawn by the always-on wakeup radio receiver in each node. The receiver activates the node upon receiving a specific signal.
The DARPA funded project seeks to design a near-zero, ultra-low-power radio. Their goal is reduce the energy drawdown during the sensor’s asleep-yet-aware phase to less than 10 nanowatts. This is an extremely ambitious goal, and combined with a required sensitivy of detecting a 1 nanowatt signal, requires improvement of a factor of a thousand compared with state-of-the art sensors. This target was chosen because it is roughly equivalent to the self-discharge during storage of a typical watch battery.
By integrating standard CMOS technologies with advanced microelectromechanical systems (MEMS) electro-acoustic resonators, usable sensitivity levels can be achieved at these power levels. This multifunctional approach helps when making decisions about sensitivity and power consumption not to feel constrained by the limitations of any one technology.