INVESTIGATION OF FLEXIBLE AND WEARABLE DEVICES FOR THE ANALYSIS OF BIOLOGICAL SIGNALS

The application potential for flexible and wearable electronics in the field of healthcare has received great interest in recent years. Flexible and wearable devices based on soft, biocompatible materials can be comfortably attached to the human skin for continuous health monitoring. In this work, we present two novel wearable bioelectrical impedance analysis (BIA) systems for body composition measurement. First, we developed a wearable ring-based BIA system for body fat monitoring. The wearable ring contains flexible copper electrodes to interface with the human body. The device is tested on 40 healthy volunteers and the results demonstrate a high correlation with an off-the-shelf body fat monitor. Second, we developed flexible BIA systems on paper and plastic substrates and compared their performance. The paper-based system demonstrates stronger adhesive contact with the electronic components while the plastic-based system provides lower power consumption and lower electrode impedance. Last, we proposed a novel temperature sensor on a polydimethylsiloxane (PDMS) substrate that can compensate for the deformation-induced resistance variation and measure temperature with minimum errors. The compensation method enhances the competence of flexible temperature sensors and increases their potential for applications in wearable electronics.