A near-threshold, multi-node, wireless body area sensor network powered by RF energy harvesting

• Published in: Proceedings of the IEEE 2012 Custom Integrated Circuits Conference pp. 1 - 4
• Main Authors: Jiao Cheng, Lingli Xia, Chao Ma, Yong Lian, Xiaoyuan Xu, Yue, C. P., Zhiliang Hong, Chiang, P. Y.
• Format: Conference Proceeding
• Language: English
• Published: IEEE 01-09-2012
• Subjects: Base stations; Electrocardiography; Rectifiers; Synchronization; Time division multiple access; Wireless communication; Wireless sensor networks
• ISBN: 9781467315555; 1467315559
• ISSN: 0886-5930; 2152-3630
• DOI: 10.1109/CICC.2012.6330681

A wirelessly-powered, near-threshold, body area network SoC supporting synchronized multi-node TDMA operation is demonstrated in 65nm CMOS. A global clock source sent from a base-station wirelessly broadcasts at 434.16MHz to all sensor nodes, where each individual BAN sensor is phase-locked to the base-station clock using a super-harmonic injection-locked frequency divider. Each near-threshold SoC harvests energy from and phase locks to this broadcasted 434.16MHz waveform, eliminating the need for a battery. A Near-V T MICS-band OOK transmitter sends the synchronized local sensor data back to the base-station in its pre-defined TDMA slot. For an energy-harvested local V DD =0.56V, measurements demonstrate full functionality over 1.4m between the base-station and four worn sensors, including two that are NLOS. The sensitivity of the RF energy harvesting and the wireless clock synchronization are measured at -8dBm and -35dBm, respectively. ECG Lead-II/Lead-III waveforms are experimentally captured, demonstrating the end-to-end system application.