High-temperature stable piezoelectric resonators are coated with oxide electrodes. The impact of the oxide electrode conductivity on the mass sensitivity and on the resonance frequency of the device is described by electrical and mechanical models, which are used to analyse the experimental data. Furthermore, the impact of an increasing oxide electrode conductivity is discussed with respect to the application of oxide electrodes and for gas sensing.

This work shows a possibility of assembly and connection technology for use under high temperatures up to 1000 °C. A packaging concept was developed, and all the necessary material and joining technologies have been verified to be suitable for use at 1000 °C. A working sensor was built and measured in comparison to the resonator alone. All packaging materials and structures were measured electrically and dielectrically. Equivalent circuits for the packages up to 2 MHz and 1000 °C are available.

Temperature sensors based on piezoelectric devices enable precise measurement of temperature changes in harsh environments such as high temperatures or aggressive atmospheres. In the case of this device, the change in the temperature is detected by means of the changing resonance frequency of the sensor. Here a sensor device based on catangasite (an isomorph of quartz) is presented. We discuss its behavior at elevated temperatures and confirm that it can successfully operate up to 1030 °C.

In a very specific way, this research paper shows how established systems – in this case a commercial soot sensor for the automotive sector – can be optimized by diving deep into the basic research. The approach here is to link macroscopic observations or signal behavior with processes taking place on the atomic level. Taking these fundamental processes into account, the sensor's specific response time could be shortened effectively by a change in operating strategy – without any design changes.

Epitaxially grown electrodes for high-temperature stable piezoelectric transducers are prepared by pulsed laser depostion. To adjust the stoichiometry in the films, oxygen partial pressure, target composition and deposition temperature are varied. Langasite films with enhanced conductivity are deposited, serving as electrodes for nearly monolithic piezoelectric resonators. These resonators show strong admittance maxima for their 1st, 3rd and 5th harmonics and are not affected by spurious modes.