bei Google ScholarTitelangaben
Fischerauer, Gerhard:
Microwave acoustic sensors : From chemical to electrical signals.
2005
Veranstaltung: SSD 2005
, 21.-25.03.2005
, Sousse, Tunisia.
(Veranstaltungsbeitrag: Kongress/Konferenz/Symposium/Tagung
,
Vortrag
)
Abstract
Mass-sensitive chemical sensors generate electrical signals such as frequency changes in response to the selective sorption of molecules. The sensors tend to respond slowly owing to the fact that the chemical species to be bound in the selective sensor film diffuses into the film with characteristic diffusion coefficients on the order of only 10^(-17) m²/s. This contribution presents a model-based sensor signal processing strategy capable of predicting the steady-state response soon after an analyte concentration change, thereby reducing the effective response time by as much as an order of magnitude. To be more specific, the sensor is characterized by an analytic model which is valid for all mass-sensitive sensors the dynamic behavior of which is dominated by diffusion effects. The impulse response turns out to be proportional to the Jacobian theta function theta2(0,exp(-pi²*t/t0)) where t0 is a characteristic time. Based on this result, we proceed to derive a formula that expresses the sensor input (the time-dependent analyte concentration) in terms of the sensor output (the time-dependent frequency shift) in closed form. The model is validated by way of measured sensor characteristics and by comparing its predictions to known numerical results. A signal processing algorithm based on the model is presented and discussed. Finally, the closed-form solution is applied to the steady-state prediction problem. We present an algorithm which effectively reduces the sensor response time to concentration steps by as much as one order of magnitude. The improvement upon the raw sensor response is the better, the less noisy the measured data are. This is because one has to smooth the data before looking for signal features indicating a concentration step, an operation which introduces a time lag relative to the raw sensor data. An example serves to demonstrate the effectiveness of the prediction algorithm together with either a simple moving-point averaging or a Savitzky-Golay (polynomial least-squares) filter.
Weitere Angaben
| Publikationsform: | Veranstaltungsbeitrag (Vortrag) |
|---|---|
| Begutachteter Beitrag: | Nein |
| Keywords: | Mass-sensitive chemical sensors; SAW; QMB; dynamic response; analytic model; diffusion |
| Institutionen der Universität: | Fakultäten > Fakultät für Ingenieurwissenschaften > Lehrstuhl Mess- und Regeltechnik > Lehrstuhl Mess- und Regeltechnik - Univ.-Prof. Dr.-Ing. Gerhard Fischerauer Fakultäten Fakultäten > Fakultät für Ingenieurwissenschaften Fakultäten > Fakultät für Ingenieurwissenschaften > Lehrstuhl Mess- und Regeltechnik |
| Titel an der UBT entstanden: | Ja |
| Themengebiete aus DDC: | 600 Technik, Medizin, angewandte Wissenschaften > 620 Ingenieurwissenschaften |
| Eingestellt am: | 30 Nov 2021 13:57 |
| Letzte Änderung: | 30 Nov 2021 13:57 |
| URI: | https://eref.uni-bayreuth.de/id/eprint/68047 |