Highly Sensitive Printed Accelerometer for Biomedical Applications

This thesis introduces a highly sensitive single-axis printed accelerometer based on a flexible paper substrate. The accelerometer is fabricated by cost-effective silver nano ink printing technologies, and consists of a suspended parallel-plate sensing capacitor. By designing the suspension bridge and proof mass structures, the sensitivity to vertical accelerations is optimized based on simulation results. The optimized design with two long ellipse-shaped bridges exhibits a capacitive sensitivity of 20 fF/g at z-axis acceleration of 1-10 g. A wearable sensing system is proposed which composes of the light-weight flexible accelerometer integrated with a readout circuit. The bandage-type accelerometer system can be conformally attached to various positions on human body for motion detection as well as obtaining vital signs such as human pulse and respiratory rate. Thus, these features allow unobtrusive continuous monitoring of various vital signs and physical activities and acting as a multifunctional sensor in health monitoring system.