Conception and realization of a novel design for a capacitive pressure sensor with high sensitivity and linear response

Abstract

In order to improve the performance (linearity and sensitivity) of capacitive-based diaphragm pressure sensors, a new design is proposed. The non-linearity is improved by eliminating the capacitance of a small area in the central region of the sensor. In contrast, the sensitivity is improved by enhancing the contribution of the edges of the sensor, which leads to a structure where the distance between the fixed and movable diaphragms is non-uniform. Unlike the other research works, we focus on the case of large deflections. The mathematical model allowing the determination of the capacitance as a function of pressure for this new design is presented. Three prototypes with different sized non-metalized central areas are successfully fabricated using 3D printing technology and machining process.Simulation results show that this form allows a non-linearity inferior to 1% if the reference capacitor is variable.