Pull – in analysis of L – shaped meandered capacitive pressure sensor at ultra low pressures

Abstract

Pressure sensors in the range of 0 – 100 Pa are used in medical ventilators to monitor and control the air pressure delivered to patients during breathing assistance. They ensure precise control of low-pressure airflow in respiratory support systems. In this paper, an l-shaped meander and circular diaphragm based capacitive pressure sensor is designed and analyzed at ultra-low pressures. The pull – in voltage of the design is evaluated and observed to be 7.34 V where the electrostatic force is observed as 8.2 µN. The deflection of the diaphragm at various voltages less than the pull – in voltage is analyzed by applying the external pressure (measurand) and observed that the impact of electrostatic forces is weak when the driving voltage is less than half of the pull – in voltage.