Separation of Sensitivity Contributions in Tin Oxide Thick Film Sensors by Transmission Line Model Measurements at Isothermal and Thermally Modulated Operation

Transmission line modelling (TLM) techniques were used to study the sensitivity behaviour to CO and propene in distinct regions of tin oxide thick film gas sensors operated in isothermal and thermo-cyclic mode. The sensitive layer showed an increased sensitivity to propene in the vicinity of the Pt electrodes at isothermal operation and pronounced specific features at thermo-cyclic operation. Simulation by Finite Element Analysis (FAE) gives insight into the electrical behaviour of the contact area and enables a detailed analysis of the thickness dependence of sensitivity effects.