以聚乙烯醇薄膜塗佈於表面聲波元件之濕度感測特性之研究

Humidity Sensing Characteristics of Polyvinyl-Alcohol Coated Surface Acoustic Wave Devices

10.29948/JAE.200607.0006

陳雲田(Yun-Tien Chen)；高慧玲(Hui-Ling Kao)

聚乙烯醇薄膜 ； 表面聲波共振器 ； 濕度感測器 ； PVA thin film ； SAW resonator ； humidity sensor

先進工程學刊

1卷1期（2006 / 07 / 01）

45 - 48

繁體中文

本研究以聚乙烯醇薄膜塗佈於在表面聲波元件上，製作濕度感測器並研究其感測能力。我們量測表面聲波濕度感測器之相對濕度對中心頻率和插入損失的影響，量測範圍從30至90%的相對濕度。當聚乙烯醇薄膜厚度在3000Å，我們獲得中心頻率差有1517KHz、插入損失差有-10.31dB的變化範圍。另外，我們也研究該感測器之水氣吸收與去吸附的短期再現性與磁滯(Hysteresis)性之影響。實驗結果顯示聚乙烯醇薄膜具有一個良好濕度感測性質，能提供至表面聲波共振器應用在較高的相對濕度環境之感測。

Highly sensitive surface acoustic wave (SAW) humidity sensors have been fabricated by spin-coating polyvinyl-alcohol (PVA) thin film on the SAW resonators. The transmission properties of the SAW sensor, including center frequency and insertion loss will be studied at a relativity humidity ranging from 30 to 90%. Frequency deviation of 1517 KHz and insertion loss deviation of -10.31 dB are obtained when the PVA thin film thickness has been increased to about 3000Å in the variation of relative humidity. The short-term repeatability and the hysteresis of water absorption and desorption cycle will be examined. The results have justified the suitability for the PVA film coated SAW resonators in the application of sensing humidity at a higher relative humidity.