Energy-Efficient Wireless Connectivity and Wireless Charging for Internet-of-Things (IoT) Applications

Passcode: 0810

During the recent years, the Internet-of-Things (IoT) is rapidly evolving. To date, the world has deployed billions of “smart” connected things. However, battery lifespan exhibits a critical barrier to scaling IoT devices. The main objective of this thesis is to develop architectures to achieve energy-efficient wireless-connectivity and wireless-charging for self-powered IoT devices. In the first part of the thesis, I introduce low power radios that are compatible with the Bluetooth Low-Energy (BLE) standard. Number of BLE transmitter (TX) and receiver (RX) architectures have been presented. The low power operation is achieved in both the network and physical layers utilizing techniques like: backchannel communication, duty-cycling, open-loop transmission/reception, PLL-less architectures, mixer-first architecture, antenna-chip co-design for quadrature generation and discrete-time GFSK demodulation.

In the second part, I introduce passive nonlinear resonant circuits to achieve wide-band RF energy harvesting and robust wireless power transfer circuits. Nonlinear resonant circuits modeled by the Duffing nonlinear differential equation exhibit interesting hysteresis characteristics in their frequency and amplitude responses that are exploited in designing self-adaptive wireless charging systems. In the wireless power transfer scenario, coupled nonlinear resonators are used to maintain the power transfer level and efficiency over a range of coupling factors without active feedback control circuitry.

Chair: Professor David Wentzloff & Co-Chair Professor Amir Mortazawi