An improved capacitance pressure sensor with a novel electrode design

Abstract

Pressure sensors are one of the most widely used sensors in many process loops. It is said that around two-thirds of the process loop contains at least a pressure sensor, thus making it very important to have a pressure sensor with higher accuracy, sensitivity, etc. The capacitance type pressure sensor is one of the variants of pressure sensors based on the principle of change in capacitance for change in input pressure. The objective of the proposed work is to design a novel pressure sensor with improved sensitivity and accuracy as compared to a conventional diaphragm-based capacitance pressure sensor. The shape and pattern of electrodes used in the capacitance pressure sensor are varied without affecting the overall dimensions. The obtained capacitance is converted to voltage with the help of a signal conditioning circuit, which is further linearized using regression algorithms. From the results obtained it is seen that the proposed sensor has an improvement in sensitivity by a factor of 79 over the conventional diaphragm pressure sensor of similar dimension and composition. The proposed method on implementation in real-life resulted in a root mean square percentage error of 0.46%.