An Engineering Approach for Modeling and Design of a Diaphragm Based Comb Drive Capacitive Pressure Sensor

The Microelectromechanical (MEMS) diaphragm based comb drive capacitive pressure sensor has two stages, Mechanical (Diaphragm) and Capacitive (Comb Drive). The diaphragm displaces in response to apply pressure and the displacement moves the movable comb structure. The two most common architectures of comb drive are single side comb structure and double fold comb structure. In this paper, an impressive technique for designing and modelling of single side comb structure capacitive pressure sensor is being presented. A mathematical model of the sensor is derived and the model simulates the designed structure with the COMSOL Multiphysics Simulator. The Mechanical Sensitivity, Electrostatic sensitivity and Overall Sensitivity are studied for the designed structure. A comparative study of the mathematic analytical values and simulated output values are examined and are found very much closed to each other. The various parameter like Young’s Modulus, Poisson’s Ratio, Dimensions and Structure of the pressure sensor, number of comb fingers and dimension of the comb finger affecting the sensitivity is widely discussed. Keywords: coupler, fringing effect, electrostatic sensitivity, mechanical sensitivity.