Battery-Free Wireless Sensors for Internet-of-Things and Cyberphysical Systems

Zero-power ubiquitous wireless sensors have been the subject of intense research in the past few years because of their wide uses in internet-of-things (IoTs), industrial 4.0, smart cities, wireless healthcare and environmental monitoring. Compared to the conventional wired connection systems, wireless platforms have the advantages of reduced area occupation, more mobilities of devices and longer interrogating distance, which enable a virtually ubiquitous access to information in a communication network. However, the development of these ever-increasing wireless nodes and the combination of heterogeneous networks have already generated a space-crowded and rich-scattering environment, which require future wireless systems with the capability to effectively suppress the electromagnetic interference and efficiently optimize the usage of space, power, and communication bandwidth. This work will theoretically and experimentally study innovative RF solutions to address the aforementioned challenges, including but not limited to (i) Compact and hybrid-fed antennas for harmonic wireless sensing applications; (ii) Absolute wireless sensing approach based on harmonic analysis enabled by frequency-hopping spread spectrum; (iii) Flexible harmonic sensors with multiplexed sensing capabilities for rapid, contactless microfluidic diagnosis.