Title :
Multistrip couplers for surface acoustic wave sensor application
Author :
Becker, H. ; Rupp, C. ; Schickfus, M.v. ; Hunklinger, S.
Author_Institution :
Inst. fur Angewandte Phys., Heidelberg Univ., Germany
fDate :
7/1/1996 12:00:00 AM
Abstract :
We present a new surface acoustic wave gas sensor utilizing a multistrip coupler on LiNbO/sub 3/ and LiTaO/sub 3/ substrates and using copper phthalocyanine as a sensor layer for NO/sub 2/. The sensor signal originates from surface conductivity changes induced by the adsorbed NO/sub 2/. This variation in conductivity leads to a changing coupling efficiency of the multistrip coupler and thus to variations in the insertion loss of the device. Rayleigh and shear wave devices with operating frequencies of 170 and 243 MHz have been tested. A sensitivity of better than 1 ppb NO/sub 2/ in air was achieved.
Keywords :
gas sensors; surface acoustic wave couplers; surface acoustic wave sensors; surface conductivity; 170 MHz; 243 MHz; LiNbO/sub 3/; LiNbO/sub 3/ substrate; LiTaO/sub 3/; LiTaO/sub 3/ substrate; NO/sub 2/; Rayleigh wave device; adsorbed NO/sub 2/; copper phthalocyanine; coupling efficiency; insertion loss; multistrip coupler; shear wave device; surface acoustic wave gas sensor; surface conductivity; Acoustic sensors; Acoustic waves; Conductivity; Copper; Couplers; Frequency; Gas detectors; Insertion loss; Surface acoustic wave devices; Surface acoustic waves;
Journal_Title :
Ultrasonics, Ferroelectrics, and Frequency Control, IEEE Transactions on
