Novel impedance interface for resonant high-temperature gas sensors

In order to analyze the behavior of resonant high-temperature gas sensor, the measurement of frequency shift and of resistance change is suitable. Therefore, fast impedance analysis based interface electronics has been developed to measure the frequency shift and the high damping of such resonant sensors. By using a direct-sampling-technique, the quantity of analog components is reduced. In consequence, the measurement period and offset compensation have been improved. An application example for highly damped resonant high-temperature gas sensors is described, based on langasite resonator with titanium dioxide film acting as an oxygen partial pressure sensor at high-temperature process environments. In contrast with commercial impedance analyzer this interface electronics is realized on a single printed circuit board which is well suited for industrial sensor applications based on impedance spectroscopy.