Wireless Vital-sign Detection Based on Improved Arc-Chord Approximation Demodulation

It's a hot topic to detect vital-sign in a non-contact approach. Apart from the motion detection on frequency-domain such as heartbeat rate and respiration rate, Doppler Radar sensors can be utilized to obtain the vital-sign in the time-domain to get more detailed information. To overcome the drawbacks of traditional phase demodulation which has to find direct current (DC) offsets for accurate detection, we propose the improved arc-chord approximation approach to avoid the complex and unstable result in linear demodulation. The crucial fitting procedure in the arc-chord approximation is innovatively implemented by the mean of vector phase (MVP) method. Both theory and numerical simulation are conducted in this paper to show the effectiveness of our method.