Research On The Design And Integration Methodology Of The Capacitive Passive Multi-parameter LTCC Sensor

The in-situ measurement technology in high-temperature environments has great demandsin the fields of aeronautics, astronautics, mining, metallurgy and industrial automation etc.Currently, conventional silicon-based sensors cannot operate up to250℃due to the limitedmaterial properties and the signal extraction method. Owing to the wonderful high-temperaturestability of ceramics, ceramic-based passive sensors have currently been the research hotspotof in-situ measurement technique. However, existing high-temperature resistant passive sensorscan only sense single parameter, thus making them quite difficult to meet the requirement ofmulti-parameters measurement in high-temperature environment with low cost and minimumpower consumption. So this paper proposed a LTCC microassembly technique-based capacitivepassive multi-parameter sensor, and focused the research on the design and integrationmethodology of the proposed sensor, which eventually presented a novel idea for in-situmeasurement technology in high-temperature environment.By studying the relative fundamental theory of the multi-parameter sensor, the analyticalcircuit model of the sensor was established. Based on the proposed theoretical model, the factorswhich influence the multi-parameters signal readout were studied, and the coupling and transfermechanism among heat, force and electrical signal of the sensor under the complex environmentwas also presented herein. Specifically, the coupling and transfer model between heat andelectrical signal of the temperature sensing LC tank was given, and also the coupling andtransfer model among heat, force and electrical signal of pressure sensing LC tank.Based on research results of the fundamental theory, a three dimensional integratedcapacitive passive sensor structure for simultaneous temperature and pressure sensing wasdesigned. Furthermore, the sensor performance was simulated by combining theoreticalcalculation and ADS EM simulation. The sensor was successfully fabricated by LTCC technology, and the optimized sintering curve for pressure sensitive cavity without the vent holewas explored and obtained. The fabricated sensor was tested under high-temperature pressurecomplex environment, which demonstrated the pretty good temperature and pressure sensitivityof the sensor within400℃and2.0bar.Finally, the multi-parameter crosstalk de-coupling problem of the proposed capacitivepassive multi-parameter sensor and the temperature compensation technique for capacitivepassive pressure sensing were studied and discussed herein. By mathematical deduction，themulti-parameter crosstalk de-coupling algorithm and the temperature compensation algorithmwere preliminary established and sequentially verified by substituting measured data, whichlaid preliminary research foundation for the future practical use of the capacitive passive multi-parameter sensor.