The stability of the capacitive ceramic sensor for measuring air pressure depends on the stability of the capacitive sensing structure and the accuracy of the electronics for signal processing. The tests performed on the prototype sensors showed the stability of the zero-pressure output within the accuracy region of the AD7746 capacitance-to-digital converter.
F.08 Development and manufacture of a prototype
COBISS.SI-ID: 23130919The results of the research and development of the technology for producing 3D LTCC structures with channels and buried cavities (air gaps) for the capacitive sensor were presented. The technological approaches with the sacrificial layers and without were considered. Particularly critical are the structures with the larger membranes with a thickness below 150 um. The test structures without sacrificial layers were manufactured and characterised.
F.09 Development of a new technological process or technology
COBISS.SI-ID: 21728551An LTCC-based CPS realised by using the technology without the sacrificial layers were considered for applications in the pressure range 0-300 mbar . The prototypes with and without the readout electronics based on a capacitance-to-digital conversion were realised with AD7746. Special attention was paid to the evaluation of the capacitive ceramic structure behaviours and the temperature compensation and linearization of the sensor’s characteristics were carried out.
F.08 Development and manufacture of a prototype
COBISS.SI-ID: 22022183Some results of the development of the technological procedure for producing 3D LTCC structures with buried air gaps under the thin diaphragm, which are essential for capacitive sensor, were presented. The influence of the technological parameters and the structure geometry on the sensors characteristics were analysed. The feasibility of the piezoresistive pressure sensors with the low-power consumption (< 0.05 mW) was also considered.
F.02 Acquisition of new scientific knowledge
COBISS.SI-ID: 22021927It is important for the design of a CCPS that the ceramic structure with an air-gap between the sensing capacitor electrodes is not an “ideal” capacitor. The geometry and the dielectric properties of the ceramic body as well as the surrounding atmosphere normally influence the capacitance of the sensor, not only the medium between the electrodes of the sensing capacitor and their geometries. In order to analyse the effects of the geometry/material parameters numerical models were used. In several iterations the design was optimised and the stability and resolution of the sensor were improved.
F.08 Development and manufacture of a prototype
COBISS.SI-ID: 24233511