We welcome our next speaker, Dr. Edwin Chihchuan Kan, who is a Professor here at Cornell.
Wearable RF Sensors for Vital Signs and More
Abstract: The fundamental principle of sensing is to couple sufficient energy into the area of interest. To probe inside human body, ultrasound, X-rays and radio-frequency (RF) waves in certain frequency ranges have acceptable dispersion and loss for accurate external measurements. A new type of wearable RF sensors, based on near-field coupling in the band of 300 MHz – 6GHz, will be introduced. The sensor, named as near-field coherent sensing (NCS), can accurately read large and small dielectric boundary motion inside the body in a broad spectrum over clothing and animal surface coverings, as well as from furniture or habitats. The sensing signal can ride on established multiplexed RF channels with digital isolation to achieve multiple and flexible implementation. For biomedical applications, we have demonstrated accurate sensing of heartbeats, respiration, pulses, vocal cords and tissue vibration to derive the heart rate, seismocardiogram, blood pressures in the systemic and pulmonary circulation, heart sound, breath rate, lung volume, breath sound, and glottal sound. The sensor is comfortable, convenient and covert, and can thus be used for continuous long-term monitoring, especially for alertness and stress derivation without bias. For animal applications, we have read vital signs from animals with various sizes and surface coverings, including mice, rats, hamsters, birds, fish, tortoises, dogs, cows and even sea elephants! Most animals under study are now aware of the existence of the sensor!
Due to the high sensitivity and broad bandwidth for NCS, these sensors can also be “worn” on robots and smart buildings for feedback control and non-intrusive structural integrity monitoring. The RF signal penetrates deeply into building materials and water and can achieve similar high sensitivity and bandwidth. We can additionally use a passive RF marker like an RFID (RF identification) tag to be embedded into structures for reading of specific location. This approach can provide a spatial resolution of less than 50 microns in air and less than 5 microns in water with a sampling rate of greater than 1 kHz.
Bio: Edwin C. Kan received the B.S. degree from National Taiwan University in 1984, and the M.S. and Ph.D. degrees from the University of Illinois at Urbana-Champaign in 1988 and 1992, all in electrical engineering. From 1997, he was an Assistant Professor with the School of Electrical and Computer Engineering (ECE), Cornell University, Ithaca, NY, where he is now a Professor in the fields of ECE and Applied Math. His main research areas include biosensors, RF indoor locating and tracking, RFID, CMOS technologies, semiconductor devices, flash memory, and numerical methods for PDE and ODE. Dr. Kan received the Presidential Early Career Award for Scientists and Engineer (PECASE) from President Bill Clinton in October 2000. He has published over 270 journal and referred conference papers and has graduated 30 Ph.D. students. He also received several inventor and teaching awards from Cornell Universities.
