SBIR Phase I: Novel MEMS Pressure Sensor

This Small Business Innovation Research Phase 1 research project will develop a novel MEMS capacitive pressure sensor which may be used for making highly accurate water depth measurements. Intended for use in regulated, long-term, unattended environmental monitoring of ground water, the device will meet or exceed stringent Federal and State regulations requiring an accuracy of at least 0.01 foot to a depth of 500 feet, or 0.002% of full-scale reading. This project involves the study of at least three MEMS device geometries, embodying designs that provide either redundancy or multiple pressure measurement ranges. In addition, at least two electronic circuit topologies will be studied for suitability in interfacing with existing commercial devices. The inherent non-linear behavior of the device will pose significant challenges in both areas. However, the non-linear characteristic of the sensor yields a large dynamic range of operation, which is highly desirable for this target application. The commercial merits of this project have immediate utility in the target market of environmental monitoring of ground water. Improved monitoring of ground water has clear societal benefits. In recent history, the EPA has migrated from site remediation to site monitoring. Accurately predicting where contaminants might flow requires precise modeling of water percolation, aquifers, and surface water flow. A low power sensor will allow for the deployment of entire networks which can more precisely monitor groundwater behavior over a greater distance with a faster measurement rate than current technologies. Providing a physically small device will enable the use of low cost, small diameter bore holes for underground monitoring, reducing installation costs.