New SAW humidity sensor using double-coated hygroscopic film

Author

Furukawa, Shoji ; Obana, Masahiro ; Nomura, Tooru

Author_Institution

Dept. of Comput. Sci. & Electron., Kyushu Inst. of Technol., Fukuoka, Japan

Volume

1

fYear

1995

fDate

7-10 Nov 1995

Firstpage

539

Abstract

We propose a new surface acoustic wave (SAW) humidity sensor using double-coated hygroscopic film in order to improve the dynamic range of the relative humidity and the adhesion of the polymer film to (128° rot Y-X) LiNbO₃ substrate. The effect of the physical constants of the material on the SAW propagation character has been investigated by both numerical calculation and experiment. As a result, it is found that the change in the SAW velocity (sensitivity) becomes larger (about 180%) by using the hygroscopic film having large stiffness constants, and the adhesion of the film is very much improved by using the double-coated structure

Keywords

adhesion; humidity sensors; polymer films; surface acoustic wave sensors; LiNbO₃; LiNbO₃ substrate; SAW humidity sensor; adhesion; double-coated hygroscopic film; dynamic range; polymer film; relative humidity; stiffness constant; surface acoustic wave velocity; Acoustic propagation; Acoustic sensors; Acoustic waves; Adhesives; Delay lines; Dielectric substrates; Humidity; Piezoelectric films; Polymer films; Surface acoustic waves;

fLanguage

English

Publisher

ieee

Conference_Titel

Ultrasonics Symposium, 1995. Proceedings., 1995 IEEE

Conference_Location

Seattle, WA

ISSN

1051-0117

Print_ISBN

0-7803-2940-6

Type

conf

DOI

10.1109/ULTSYM.1995.495635

Filename

495635