Numerical Simulation Analysis of Microstructure of Dielectric Layers in Capacitive Pressure Sensors

Sensitivity and linearity are important performance metrics of flexible sensors in the application. An effective approach toward improving the performance of capacitive pressure sensors (CPSs) is the appropriate design of the microstructure of the dielectric layer. Using the finite-element modeling in an integration of Abaqus and COMSOL Multiphysics, we propose a methodology to simulate the deformation and capacitance responses of CPS upon external pressure; the numerical results agree well with the experimental data. With the attempt to improve the performance of widely used pyramidal and cylindrical microstructure-based CPS, the effects of microstructure geometric parameters and mechanical property of materials, such as the elastic modulus, length of hemline, sidewall angle, height, and size on the pressure response, were investigated, and the sensitivity and nonlinear error were also analyzed. It has been found that the sensitivity and linearity are more sensitive to elastic modulus and are less sensitive to height. With the same sensitivity, the cylinders-based CPSs have higher linearity, while the pyramids-based CPSs have larger pressure measuring range. The obtained results could provide reference information for the design of CPS with improved application characteristics.