Dynamic Mathematical Modelling of Capacitive Pressure Sensors using Different Materials for Healthcare Applications

Abstract

This paper discusses the principle, design and theoretical dynamical modelling of MEMS capacitive pressure sensors with different material properties results that have been simulated as well as compared. The properties of the material ensure that sensor performance analysis for operating pressure range 0-25kPa. This work discusses Timoshenkos plate deflection theory and follows the pull-in phenomenon. One important factor that could influence the performance of a MEMS capacitive pressure sensor is the structure of the diaphragm. The active area of this sensor is made up of 0.5 mm0.5 mm and the cavity size are 2m. According to the simulations, the optimized parameters have higher linearity and greater sensitivity than the initial parameters. The comparison of results shows that Aluminium material gives the highest deflection and better capacitance sensitivities which is about 88 pF/pa and is more linear with the applied pressure than other materials. The behaviour of the touch mode capacitive pressure sensor in terms of the temperature dependence of capacitance is analysed and repeatability error has been reduced. This configuration of touch mode pressure sensor is promising for the use in health monitoring devices like patient blood pressure due to small pressure fluctuation.