A High Precision Nanomaterial Based Surface Acoustic Wave Humidity Sensor
Date Issued
2007
Date
2007
Author(s)
Chou, Tai-hsu
DOI
en-US
Abstract
There is a growing demand for developing a sensing system to measure relative humidity not only for human comfort but also for industry applications. Up to date, various sensitive materials with good sensing characteristics are mainly polymers. Thus, development of the real-time and precise humidity sensor which utilizes easy synthesis and stable sensing materials at room temperature is highly needed. A good sensor should be characterized by high sensitivity, wide dynamic range, fast response, good reproducibility, easy interface electronics, small size, and minimum cost. Existing sensors with single sensing system are hard for matching all these criterions. However, surface acoustic wave (SAW) sensing devices are promising candidates to pursue the above goals.
In this thesis, a 145 MHz based SAW resonator was fabricated and integrated with the amplifier to form an oscillator. To function as a humidity sensor, HCL-doped and CSA-doped polyaniline nanofibers were coated on the delay line of the resonator as the sensing film. Moreover, dual channel configuration was constructed for reducing environmental influences such as temperature and pressure, etc. Then, the sensing devices were exposed to various relative humidity to investigate the performances and compared the efficiency between different materials on room temperature. Good linearity and high sensitivity were acquired toward various relative humidity sensing.
Subjects
表面聲波
濕度感測器
聚苯胺
Surface acoustic wave
Humidity sensor
Polyaniline
Type
thesis
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