A Wireless SAW Hybrid Sensor for Simultaneous Temperature and Humidity Measurements
Date Issued
2007
Date
2007
Author(s)
Wang, Rung-De
DOI
en-US
Abstract
The control of relative humidity (RH) and ambient temperature is required for a broad spectrum of human comfort, medical instrument, chemical industry, agriculture, and etc. To reduce cost and increase lifetime, a passively wireless sensor which is capable of measuring relative humidity and ambient temperature should be developed to meet this demand.
In this thesis, an impedance loaded SAW hybrid sensor is successfully accomplished by integrating a 433MHz 128˚ YX-LiNbO3 based SAW tag with external sensors such as thermistor and resistive RH sensor. The combination exhibits attractive advantages, such as wireless sensing, passive operation, and size minimization. First, the coupling-of-modes model was employed to design the SAW tag and predict its frequency response. To enhance the sensitivity of the resistive RH sensor, CSA-doped polyaniline nanofibers were utilized as sensitive film due to its easy synthesis and stable performance. Finally, the hybrid sensor was constructed and measured to evaluate performances. The results indicate our SAW hybrid sensor exhibits good linearity and high sensitivity.
Subjects
表面聲波
無線
被動式
阻抗
相對濕度
聚苯胺
奈米纖維
Surface acoustic wave
Wireless
Passive
Impedance
Relative humidity
Polyaniline
Nanofiber
Type
thesis
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