Modeling and Performance Comparison of Screen-Printed, Impedance Spectroscopy Probes for Harsh Environments

Abstract

This paper compares the simulated performance of three different screen-printed probe geometries for Electrochemical Impedance Spectroscopy probes for use in harsh environments. The best performing probe, which is equipped with guarding electrodes that are proven to help with the electric field uniformity, shows a linear response with the medium's resistivity using a 1 kHz sinusoidal input current with a sensitivity of 0.163 mV/Qm in the range of 2.5 Qm to 50 Qm in a medium with relative permittivity of 20. Additionally, the phase shift shows a linear relationship to the medium's relative permittivity and a sensitivity of 0.1 degrees/εr in the range of 5-81 using a 1 MHz sinusoidal input current. The equivalent circuit models of the probes were constructed and the values of the components have been reported. The best performing probe was fabricated and experimentally tested to back up the theoretical simulations and proposed models. The experimental and simulated values are within a ±6% error margin.