Sensitivity Enhanced Touch-mode Capacitive Pressure Sensor with Double-cavity

Abstract

Capacitive pressure sensors that consume less power with less temperature sensitivity have undergone many design modifications, in order to improve the performance for meeting the application needs of various fields. In this paper, the sensitivity of micro-pressure capacitive sensor is improved by adding a novel double-cavity structure and a gas hole. The double-cavity feature can amplify the amplitude of the upper diaphragm, and the gas hole can alleviate the repulsive effect of the gas pressure in the chamber on the diaphragm bending deflection. This paper provides an in-depth theoretical analysis model for the designed sensor structure using Finite Element Method Simulations. The simulated results indicate a significant enhancement in linearity range and capacitance in comparison with traditional structure. Besides, the sensor shows an enhanced sensitivity of about 1.83 times when the volume ratio of the upper cavity to the lower is 4:1, compared to the sensor having two cavities with the same volume. It is expected to realize the micro-pressure detection technology, which integrates the characteristics of high sensitivity, large linearity range, and anti-overload technology.