| Summary: | 碩士 === 中原大學 === 電子工程研究所 === 95 === Microelectronic sensor technologies attract much research interest recently. For future sensing applications, the sensitivity has become the most important requirement of sensor technologies. In this research, SAW oscillators with high sensitivity are applied as gas sensing devices. Since SAW-based oscillators are capable of showing their sensing response in the form of frequency shift, the sensitivity of SAW-based sensors can be evaluated in terms of their frequency response and readout. According to mechanism and theory of SAW device in related literature, four schemes including “center frequency”, “temperature”, “sensing area” and “thickness of absorbing polymers” in the SAW oscillators are studied for the comparison of gas detecting sensitivity. 428MHz SAW oscillators and related circuits are fabricated and compared with the 158MHz ones in vapor sensing experiments.
The experimental results show that increased center frequency, lowered operating temperature and increased thickness of absorbing polymers are proved to be effective to improve the sensitivity. The results of this research are expected to help to enhance SAW oscillators to higher sensitivity for future applications.
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