Investigations for robust and low-power heartbeat sensing using wearable, implantable and doppler-based non-contact bio-sensors
Das, Vighnesh Rudra
MetadataShow full item record
The research and development for robust, accurate and power-efficient sensors for the continuous monitoring of physiological vital signs of patients is of great importance. For example, accurate and continuous heart rate monitoring will not only provide key medical insights regarding the individual’s heart conditions, but it may also be critically important in providing life-saving treatments and therapies. This thesis, therefore, presents a study on several robust and low-power techniques for continuous heartbeat sensing using: (1) a wearable electrocardiogram (ECG) sensor; (2) an implantable cardioverter defibrillator (ICD); and (3) a Doppler-based non-contact vital signs (NCVS) bio-sensor. To realize effective wireless-assisted-living solutions and provide reliable ambulatory healthcare, low power and miniature cardiac monitoring sensor systems are essential. In this context, low-power and low-noise instrumentation amplifiers (INAs) were studied and designed to be a part of the bio-sensor analog front end (AFE) integrated circuit (IC). Circuit techniques and topologies for low-power and low-noise design were used to realize CMOS INAs, which would enable robust and battery friendly ECG bio-sensors. This thesis discusses the circuit design techniques, and presents the simulation and measurement results of the low-power CMOS INAs with and without the chopper techniques to reduce the 1/f noise. Doppler-based non-contact vital signs (NCVS) bio-sensor was also investigated for reliable and robust detection of heart rate. On the system level, the antenna evaluation of the non-contact vital sensor has been explored to understand the relationship between the antenna characteristics and heart-rate detection accuracy. The original PCB-based NCVS sensor system used in the study was designed by former students of our group, but this thesis reports the various efforts to make the system more reliable and robust.