Vital Sign Monitoring via Flexible Capacitive Sensors: A Comparative Study

We present a comparative study on flexible capacitive sensors using three different mechanisms for vital sign monitoring. To record arterial pulse and respiration rate, sensors with a parallel-plate structure and engineered dielectrics with piezoelectric (BTO, PVDF - TrFE) fillers, polyurethane foam or triboelectric frictional layers are explored in this work. The sensitivity of the sensors with alternative mechanisms are compared by placing them on different locations on the body (wrist, neck and suprasternal notch). It is found that PU foam-based sensor is most sensitive option in terms of location and spectral content. Collectively, these sensors can be used in a multimodal patch developed for monitoring respiratory health as well as other abnormalities via sensor fusion.