Title:  Noncontact cardiac signal detection using microwave Doppler radar

Committee: 

Dr. Zhang, Advisor        

Dr. Durgin, Chair

Dr. Inan

Abstract:

The objective of the research is to achieve the detection and monitoring of cardiac signals for a human subject through a microwave Doppler radar system, which provides a vital information for health monitoring. In this proposal, a noise suppression scheme and clutter removal strategies are first investigated to improve the performance of a microwave Doppler radar system for detecting an accurate and reliable cardiac signals. It is demonstrated that the proposed noise suppression scheme consisting of dual carriers and a phase locked loop could reduce the noise level and improve the signal to noise ratio by 12 dB. In addition, the clutter removal strategies through a negative feedback scheme and a frequency modulated continuous wave radar system are evaluated for improving the signal accuracy. Further investigations on what kind of cardiac signals can be captured by the radar system are conducted, which demonstrate that the radar acceleration waveform (RAW) exhibits a high similarity to seismocardiogram (SCG) in morphology and timing features within the frequency band 18-35 Hz and prove the effectiveness of RAW in representing SCG features. In addition, to achieve complete non-contact detection and monitoring of cardiac signals, a method is developed to independently extract cardiac features from RAW without using a contact electrocardiogram (ECG) sensor as that conventional SCG feature extraction methods rely on.