Title :
Multiple-frequency SAW devices for chemical sensing and materials characterization
Author :
Ricco, A.J. ; Martin, S.J.
Author_Institution :
Sandia Nat. Lab., Albuquerque, NM, USA
Abstract :
The authors have demonstrated the use of multiple-frequency SAW (surface acoustic wave) devices for chemical detection and characterization of thin-film properties. A seven-frequency SAW device was designed and fabricated with nominal Rayleigh wave center frequencies ranging from 25 to 200 MHz in square root 2 multiples. For this device, transducer periodicity, finger length, and center-to-center transducer separation all scale with the reciprocal of the center frequency. Coating this device with a thin polymer film allows the study of frequency-dependent changes in the viscoelastic properties of the polymer as a function of temperature and of the concentration of various organic solvents, which in turn provides a means for selectivity detecting these compounds. Multifrequency devices provide a means of distinguishing among the many perturbations affecting SAW propagation.<>
Keywords :
chemical variables measurement; detectors; polymer films; surface acoustic wave devices; viscoelasticity; 25 to 200 MHz; center frequency; center-to-center transducer separation; chemical detection; chemical sensing; concentration; finger length; frequency-dependent changes; multifrequency devices; multiple-frequency SAW; nominal Rayleigh wave center frequencies; organic solvents; thin polymer film; thin-film properties; transducer periodicity; viscoelastic properties; Acoustic signal detection; Acoustic transducers; Acoustic waves; Chemicals; Fingers; Frequency; Polymer films; Surface acoustic wave devices; Surface acoustic waves; Thin film devices;
Conference_Titel :
Solid-State Sensors and Actuators, 1991. Digest of Technical Papers, TRANSDUCERS '91., 1991 International Conference on
Conference_Location :
San Francisco, CA, USA
Print_ISBN :
0-87942-585-7
DOI :
10.1109/SENSOR.1991.148892
