Capacitive Pressure Sensors

Abstract

This article addresses the principles, structure, measurement, fabrication, and packaging of capacitive pressure sensors. Because micromachined technologies have been widely used in the processing of sensors, particular focus is placed on silicon capacitive pressure sensors. Three different general approaches are introduced and compared in which the response of the sensor is due to the change of the spacing, area, and dielectric permittivity under pressure. Two methods to realize the front‐end circuitry, sensing of the capacitive sensor with AC modulation (continuous‐time approach) and switched capacitor interfaces, are then discussed. The fabrication processes such as bulk silicon micromachining, surface micromachining, and monolithic integration with circuits are presented and compared. The packaging for the sensors is discussed. Recently, other materials have been considered for capacitive pressure sensors because of their excellent performance in different application fields. The progress of emerging technologies and materials is introduced and compared. Finally, the applications of capacitive pressure sensors are briefly introduced.

3D printed mould-based graphite/PDMS sensor for low-force applications

“…Nowadays, flexible sensors incorporated with microelectromechanical systems (MEMS) have become a popular choice for researchers to develop micro-structured devices for force sensing. Some of the applications include their uses as tactile sensors for biomimetic application [35] and robotic applications [36], while some of the sensors, being capacitive in nature, offering the advantages of simplicity in design and fabrication, high sensitivity, and relatively low energy consumption [37]. The application of flexible sensors for [38] applied low-force sensing specially in the field of tactile sensing, [39] used it for robotic and upper-limb prostheses, touch screens were made using it by [40] and soft tactile sensors were achieved using it by [41].…”