Modeling and Testing of a Minimally Powered SOI-DRIE MEMS Pressure Sensor for Discrete Blast Detection

MEMS diaphragms utilizing an embedded cantilever array to sense pressure were investigated in an effort to detect blast-induced loads that potentially cause mild traumatic brain injury (mTBI). Overhanging cantilever beams of varying length sequentially contacted convexly deformed diaphragms during pressure loading to enable binned binary threshold pressure sensing. Diaphragms and overhanging cantilever beam arrays photolithographically defined using double-layer SOI-DRIE processes were designed to minimize footprint and maximize sensing resolution while avoiding diaphragm fracture. Analytic models based on classical plate theory were correlated with a FEA model to guide design decisions by predicting deflection behavior of circular diaphragms under uniformly distributed pressure loads. Fabricated sensors experimentally tested under static conditions revealed good agreement with modeling, and indicated such a sensor may be well-suited for integration into a future wearable device capable of sensing potentially mTBI-causing blasts using minimal power.