Numerical simulation analysis of flexible capacitive pressure sensors based on porous pyramidal microstructures

Flexible wearable pressure sensors with high sensitivity have a wide range of applications in the field of healthcare monitoring, e-skin technology, robotic limbs, and other human–machine interaction under low pressures. For very low pressures, a sensor with high sensitivity and bulky, expensive measuring equipment is required to obtain the output signal. The incorporation of a micro-pyramidal porous dielectric section can considerably enhance the sensitivity of the capacitance-based pressure sensor. This article has employed a finite element method-based three-dimensional simulation to assess the performance of the porous microstructured capacitive pressure sensor (pmcps). The numerical results revealed a high level of agreement with the experimental data. To simplify the design and fabrication of the sensor with optimal performance, the effects of parameters such as sensor dielectric constant, dielectric layer porosity, base length, tip width, height, and inter-microstructural spacing of porous micro-pyramids were investigated using the response surface methodology. Sensitivity analysis showed that the tip width of the micro-pyramid has the greatest effect on sensor sensitivity and the least effect on the initial capacitance. Finally, equations were proposed for predicting the initial capacitance and sensor sensitivity based on the geometric parameters of the porous micro-pyramid and intrinsic properties of the dielectric section using three-dimensional finite element simulation to facilitate the ability to predict the fabrication and design process of the pmcps and optimize its performance for different applications.