Capacitive proximity sensor design tool based on finite element analysis

Purpose - The purpose of this paper is to develop a program based on three-dimensional finite element analysis to model different patterns of capacitive proximity sensors. This program can be used as a development tool to optimize the structure and size of a sensor for a desired or for a given sensitivity and linearity range and as a consequence to save sensor design time. A set of experiments have been conducted to test the tool capabilities for designing different sensor structures. Design/methodology/approach - Finite element analysis in ANSYS software was used to perform electrostatic field simulations and to calculate the capacitance between electrodes of a capacitive proximity sensor when a conducting target is placed in some distance from the sensor plate. Findings - Several capacitive proximity sensor structures have been designed, analyzed and tested to illustrate the accuracy of the simulated results obtained from the design tool. After design and implementation of a sensor and comparing the extracted and measured capacitance values, it is shown that the finite element analysis is an accurate method to extract fringing capacitance in capacitive proximity sensors in comparison to the analytical tool based on the finite difference method. Originality/value - This automatic capacitive proximity sensor design tool can optimize a sensor structure with specific shape and size to have more sensitivity or linearity according to the application in use. Moreover, the modeling program can extract characteristics of a sensor with user-defined parameters.