[Zurück]

M. Gröschl, R. Schnitzer, B. Bode, E. Benes:
"A novel admittance measurement system for resonant piezoelectric BAW sensors";
in: "Proc. 2nd Congress of Alps-Adria Acoustics Association and 1st Congress of Acoustical Society of Croatia", Acoustical Society of Croatia, Zagreb/Croatia, 2005, ISBN: 953-95097-0-x, S. 256 - 264.

Abstract: A novel general-purpose on-line measurement system for resonant piezoelectric bulk-acoustic-wave (BAW)
sensors is presented. The system supports various sensor types for different physical measurands, such as temperature,
humidity, viscosity, density and speed of sound of liquids, and film thickness. The measurement principle is based on the
determination of locus of admittance curves of the respective sensors for one or several resonances (fundamental
and/or overtones). Measurement results are calculated from the measured resonance frequencies or quality factors by
applying the appropriate sensor function or calibration data for each sensor. The system covers sensors with resonance
frequencies ranging from 30 kHz to 30 MHz. Special electronics have been developed to transform the sensor admittance
values (real and imaginary parts) to voltage signals that are acquired by the computer system. Disturbing effects
caused by the capacitance of the sensor connecting cable are minimized by special electronic circuitry. System performance
was tested successfully in combination with two different types of temperature sensors (30 MHz quartz crystal
and 6 MHz GaPO4 crystal) and two different types of viscosity sensors (56 kHz torsional mode and 2.8 MHz thicknessshear
mode quartz crystals).
Key words: bulk-acoustic-wave BAW sensor, piezoelectric resonator, piezoelectric sensor, admittance measurement

http://aleph.ub.tuwien.ac.at/F?base=tuw01&func=find-c&ccl_term=AC05938023