Characterising a PCB electrical conductivity sensor using electromagnetic simulation and a genetic algorithm

Abstract

Measuring electrical conductivity makes it possible to determine the concentration of dissolved ionic compounds in the water. Presented is a sensor developed for easily measuring the electrical conductivity of aqueous solutions. This sensor is comprised of two planar electrodes integrated onto a printed circuit board (PCB). PCB technology enables this sensor to be manufactured at high volumes for a modest cost. However, when the sensor is integrated into a PCB, it becomes difficult to analytically determine the influence the dimensions of the sensor's electrodes have on its measurements. In this research, a genetic algorithm was used to derive an equation predicting the behaviour of a PCB sensor with any reasonable electrode dimensions. Afterwards, the accuracy of this equation was evaluated by comparing its predictions to the measurements taken using actual sensors.