Wearable micro-electro-mechanical systems pressure sensors in health care: Advancements and trends—A review

Wearable technologies offer a complementary approach to clinical diagnostics by utilising a variety of physical, chemical, and biological sensors to mine physiological (biophysical and/or biochemical) data in real time (preferably continuous), in a non-intrusive or minimally invasive manner. Micro-Electro-Mechanical Systems (MEMS) pressure sensors dominate the healthcare applications especially for vital parameter sensing, as they feature the non-invasive method of diagnosis and have comparatively high sensitivity leading to better accuracy. Among them, capacitive and piezoresistive type pressure sensors have gained substantial advantages compared to other transduction devices due to high linearity, low power consumption, and low thermal coefficient. The performance review of such MEMS sensors in research and as well as market-ready devices that can be seamlessly integrated into commercial wearable products is the primary focus in this work. Challenges in the system level integration of Microsensors with the associated interface electronics and the design mitigation of such MEMS microsystems are also discussed. Design insights of analog front-end circuitry in terms of gain, noise, power and area that are crucial for any wearable applications are also comprehensively reviewed.