Biomedical Radar for Time-Varying Health Information Sensing

Biomedical radar technology has been well investigated since the 1970s. The biomedical radar can capture vital-sign signals such as respiration, heartbeat, and body movement without contact or attached sensors. Actually, these vital-sign signals are typically time-varying. The health information can be reflected in the time-varying vital-signs. This presentation will discuss how to use biomedical radar for time-varying health information sensing. Four applications have been introduced. At first, we will start our discussion by using biomedical radar for small-scale time-varying vital-sign detection. The Synchrosqueezing Transform (SST) is utilized for instantaneous vital-sign detection. It can be found that the biomedical radar can capture the time-varying vital-sign signals with a high resolution. Secondly, another critical time-varying vital-sign, blood pressure, has been obtained from the beat-to-beat arterial pulse wave acquired from the biomedical radar. Thus, we have proposed a non-contact time-varying blood pressure method by constructing a relationship between radar-acquired arterial pulse waves and blood pressure values. Thirdly, we will discuss using biomedical radar to recognize breathing disorders. In our research, the nocturnal breathing disorder, including abnormal breathing rate and pattern, can be identified from the overnight breathing signal. We have developed an automatic breathing screening method for biomedical radar based on the clinical database collected in some hospitals. At last, we extend the biomedical radar to long-term health information sensing. We use the biomedical radar to estimate the overnight sleep stage. A clinical database was collected in different hospitals with various radar sensors. With the clinical database, a sleep stage estimation model has been obtained. These experimental results all show the feasibility of biomedical radar for time-varying health information sensing.