HARMONIC RF SENSING: FROM INDOOR LOCALIZATION TO VITAL-SIGN MONITORING

Abstract

“When wireless is perfectly applied, the whole earth will be converted into a huge brain, which in fact it is all things being particles of a real and rhythmic whole.” For almost a century, electrical engineers are endeavoring to approach what Nikola Tesla predicted in 1926 for a “World Wireless System”. However, as of today, many hurdles remain when we think of all things connected rhythmically with interaction and links between the cyber and the physical worlds, because sensing of the “things”, especially “living things”, is still heavily constrained. The location and shape of objects, as well as the vital signs of people and animals are critical information to the overall systems. I will first highlight the solutions of highly reliable and accurate indoor RF ranging, localization. The demonstrated radio frequency (RF) localization method bypasses the Uncertainty-Principle mathematical model commonly seen in the radar-like system, so that the high temporal (kHz) and spatial (microns) resolutions can be achieved simultaneously with ~915 MHz signals which have deep penetration to many dielectrics of interests such as building materials and living tissues. Vital-sign monitoring is the second part from Chapter 4, including the heartbeat dynamics, respiration, and blood pressures of both central and pulmonary circulations, with the new near-field coherent sensing (NCS) approach, which not only provides unparalleled RF vital-sign signal quality and sensing capability, but also does not require skin touch or motion restraint to greatly improve the applicability to people and animals. The systems in my works can be implemented in the applications of high precision indoor locating, assisted living, RF bio-tomography, biometrics for security, wearable sensors, and clinical research. Finally, I will discuss some of the potential following directions and projects in the future works. All my works during the Ph.D. period are covered by the 27 research papers and 7 patents, which are listed at the end of this dissertation.