Sensors 2013, 13(3), 2777-2785; doi:10.3390/s130302777
Article

Multi Reflection of Lamb Wave Emission in an Acoustic Waveguide Sensor

Martin Schmitt 1,* email, Sergei Olfert 2 email, Jens Rautenberg 2 email, Gerhard Lindner 1 email, Bernd Henning 2 email and Leonhard Michael Reindl 3 email
1 Institute of Sensor and Actuator Technology, Coburg University of Applied Sciences, Am Hofbrauhaus 1, 96450 Coburg, Germany 2 Measurement Engineering Group, Faculty of Electrical Engineering, Computer Science and Mathematics, University Paderborn, Warburger Str. 100, 33098 Paderborn, Germany 3 Laboratory for Electrical Instrumentation, Department of Microsystems Engineering-IMTEK, University Freiburg, Georges-Kohler-Allee 106, 79110 Freiburg, Germany
* Author to whom correspondence should be addressed.
Received: 19 December 2012; in revised form: 9 February 2013 / Accepted: 18 February 2013 / Published: 27 February 2013
(This article belongs to the Special Issue Last Trends in Acoustic Sensing)
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Abstract: Recently, an acoustic waveguide sensor based on multiple mode conversion of surface acoustic waves at the solid—liquid interfaces has been introduced for the concentration measurement of binary and ternary mixtures, liquid level sensing, investigation of spatial inhomogenities or bubble detection. In this contribution the sound wave propagation within this acoustic waveguide sensor is visualized by Schlieren imaging for continuous and burst operation the first time. In the acoustic waveguide the antisymmetrical zero order Lamb wave mode is excited by a single phase transducer of 1 MHz on thin glass plates of 1 mm thickness. By contact to the investigated liquid Lamb waves propagating on the first plate emit pressure waves into the adjacent liquid, which excites Lamb waves on the second plate, what again causes pressure waves traveling inside the liquid back to the first plate and so on. The Schlieren images prove this multi reflection within the acoustic waveguide, which confirms former considerations and calculations based on the receiver signal. With this knowledge the sensor concepts with the acoustic waveguide sensor can be interpreted in a better manner.
Keywords: multi reflection; lamb wave; emission; acoustic waveguide sensor; surface acoustic waves; leaky lamb waves; schlieren imaging

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Cite This Article

MDPI and ACS Style

Schmitt, M.; Olfert, S.; Rautenberg, J.; Lindner, G.; Henning, B.; Reindl, L.M. Multi Reflection of Lamb Wave Emission in an Acoustic Waveguide Sensor. Sensors 2013, 13, 2777-2785.

AMA Style

Schmitt M, Olfert S, Rautenberg J, Lindner G, Henning B, Reindl LM. Multi Reflection of Lamb Wave Emission in an Acoustic Waveguide Sensor. Sensors. 2013; 13(3):2777-2785.

Chicago/Turabian Style

Schmitt, Martin; Olfert, Sergei; Rautenberg, Jens; Lindner, Gerhard; Henning, Bernd; Reindl, Leonhard M. 2013. "Multi Reflection of Lamb Wave Emission in an Acoustic Waveguide Sensor." Sensors 13, no. 3: 2777-2785.

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