Design and Analysis of a Novel MEMS Capacitive Ttire Pressure Sensor with High Sensitivity and Linearity

This paper is focused on a novel design of stepped diaphragm for mems capacitive pressure sensor used in tire pressure monitoring system. the structure of sensor diaphragm plays a key role for determining the sensitivity of the sensor and the non-linearity of the output. first the structures of two capacitive pressure sensors with clamped square flat diaphragms, with different thicknesses are investigated and their sensitivity and non-linearity are compared together. finally for increasing the sensitivity and linearity, a new capacitive pressure sensor with a stepped diaphragm is introduced. a numerical solution for determination of the accurate sensitivity of the sensor is presented. the results show that the sensitivity of the sensor is increased from 0.063 ff/kpa with flat diaphragm to 0.107 ff/kpa with stepped diaphragm and also the non-linearity is decreased from 2.37% to 1.857%. in this design, the sensor sensitivity and output linearity are increased simultaneously.