Body Orientation and Vital Sign Measurement With IR-UWB Radar Network

Radar-Based Monitoring of Vital Signs: A Tutorial Overview

“…Radar-based monitoring of vital signs is based on the idea that the chest wall of human bodies reflects the electromagnetic waves generated by a radar placed in front of it and that its quasi-periodic vibrations, resulting from respiration and heartbeat, modulate such waves. Therefore, in principle, essential information about vital signs, i.e., HR and BR, can be extracted from the reflected electromagnetic waves [27], [28], [29] and a fundamental objective, namely, contactless monitoring of vital signs, can be achieved. Note also that, compared with traditional methods, such as pneumotachography and electrocardiography, radar systems make continuous and timely BR and HR monitoring possible without entailing an additional work load for nurses.…”

Radar-based Monitoring of Vital Signs: A Tutorial Overview

“…Therefore, in principle, essential information about vital signs, i.e. heart and breath rates, can be extracted from the reflected electromagnetic waves [20][21][22] and a fundamental objective, namely contactless monitoring of vital signs, can be achieved. Note also that, compared with traditional methods, such as pneumotachography and electrocardiography, radar systems make continuous and timely breath rate (BR) and heart rate (HR) monitoring possible without entailing an additional work load for nurses.…”

“…Although the models illustrated above are accurate, a simpler representation of the heart and breathing profile has been adopted by various researchers [21,31,32]. More specifically, if T i is assumed to be equal T e , the approximate model…”

“…c) Stepped frequency continuous wave radars operating at frequencies lower than 3 GHz and in the X band are have been exploited for the estimation of the vital signs parameters of single or multiple people in [79,80] and in [81,82], respectively. d) Impulse radio UWB radars operating in the C, X and E bands and having large bandwidths (2 − 3 GHz) have been employed to measure vital parameters with high accuracy in [21,52,70,[83][84][85].…”

“…These results evidence that: a) the spectral peak associated with breathing (in correspondence of 21 acts/min) is much larger than the one related to heart beat (visible at approximately 61 acts/min); b) the second order harmonic of breathing is clearly visible at approximately 21 × 2 = 42 acts/min, whereas its third harmonic is expected at 21 × 3 = 63 acts/min. The heart signal can be extracted from the unwrapped phase through band-pass filtering [21]. In this case, a fourth order band-pass Butterworth is used to select the spectral components whose frequencies belong to the interval [0.91 Hz, 3 Hz]; its output is shown, for both radars, in Fig.…”