System-on-a-Chip UWB radar sensor for contactless respiratory monitoring: Technology and applications

Abstract

Thanks to the extremely low level of emitted power, ultra-wideband (UWB) technology is expected to be one of the most important technologies capable of supporting both, the needs of contactless sensing and ultra low-power data communication, opening to interesting opportunities for implementing innovative sensors applied to the continuous monitoring of vital parameters and their communication within wireless body area networks. In this frame, particularly relevant is the interest in radar sensors for contactless respiratory rate monitoring. Such devices are expected to be the enabling technology for a wide range of continuous bio-monitoring applications, ranging from sleep-wake classifications of drivers in vehicles to respiratory disorder diagnoses (e.g., obstructive apneas) of infants and adults, from fatigue detection for fitness users to health monitoring of patients in hospital and domestic environments. The contribution expected from continuous-time contactless monitoring systems free of any encumbrance will have a pivoting role in tackling respiratory chronic diseases and gaining a better understanding of respiratory rate variability, especially in correlations with other pathological (e.g., cardiovascular, obesity, diabetes, etc.), behavioral, and environmental risk factors. This chapter reports the key aspects of the research and development of the radar technology carried out by our group. In detail, it focuses on the implementation of a System-on-a-Chip (SoC) UWB pulse radar for respiratory rate monitoring in nano-scale CMOS technology and its experimental tests in the operating scenarios. Paragraph 1 reports an introduction to UWB pulse radar systems for contactless monitoring of vital parameters. Section SoC CMOS UWB Pulse Radar Sensor reports the SoC UWB pulse radar system for respiratory monitoring and its operating principle and building blocks. Section Field Operational Tests reports the experimental results of the field operational tests, including the detection of the respiratory rate patterns of adults and infants. Finally, the conclusions are drawn in section Conclusions.