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Journal of Micro/Nanolithography, MEMS, and MOEMS

Wireless surface acoustic wave chemical sensor for simultaneous measurement of CO2 and humidity
Author(s): Wen Wang; Chunbae Lim; Kee-Keun Lee; Sang Sik Yang
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Paper Abstract

A 440-MHz wireless and passive surface acoustic wave (SAW) microsensor was developed for simultaneous measurement of CO2 and relative humidity (RH). The developed SAW microsensor was composed of SAW reflective delay lines structured by an interdigital transducer (IDT) and several shorted grating reflectors, CO2, and water vapor-sensitive films. A theoretical model was established to predict the response mechanism of the polymer-coated SAW gas sensor. Infusion of CO2 into the chamber and humidity changes induced large phase shifts in the reflection peaks. Good linearity and repeatability were observed in the CO2 concentration of 0~400 ppm and 20~80% RH. The obtained sensitivity was ~2° ppm−1 for CO2 detection and 7.45°/%RH for humidity sensing. Temperature and humidity effects were also investigated during the sensitivity evaluation process.

Paper Details

Date Published: 1 July 2009
PDF: 6 pages
J. Micro/Nanolith. MEMS MOEMS 8(3) 031306 doi: 10.1117/1.3158610
Published in: Journal of Micro/Nanolithography, MEMS, and MOEMS Volume 8, Issue 3
Show Author Affiliations
Wen Wang, Ajou Univ. (Korea, Republic of)
Chunbae Lim, Ajou Univ. (Korea, Republic of)
Kee-Keun Lee, Ajou Univ. (Korea, Republic of)
Sang Sik Yang, Ajou Univ. (Korea, Republic of)

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