Institute of Applied Mechanics, National Taiwan University, Taipei, Taiwan.
Nanotechnology. 2010 Mar 5;21(9):095503. doi: 10.1088/0957-4484/21/9/095503. Epub 2010 Feb 8.
Using a passive wireless sensor to detect hydrogen can reach the goals of reducing cost and increasing the lifetime since the sensor can work without batteries. In this paper, a passive wireless hydrogen SAW sensor operating at room temperature has been achieved by combining a SAW tag and a resistive hydrogen sensor. The SAW tag is fabricated on a 128 degrees YX-LiNbO(3) substrate and its central frequency is 433 MHz. The resistive hydrogen sensor with the Pt-coated ZnO nanorods as the sensing film has the advantages of high stability, good repeatability and simple fabrication. The ZnO nanorods are synthesized by using the aqueous solution method and the Pt coating is employed as a catalyst for the hydrogen detection. The property of the resistive hydrogen sensor is examined before combining with the SAW tag. Results show that the resistance changes caused by the variations of relative humidity and temperature are negligible. Finally, the hydrogen SAW sensor is configured and measured wirelessly for various hydrogen concentrations at room temperature. The difference of the relative return loss caused by the hydrogen concentration variation is obvious and recognizable. All responses show that the proposed hydrogen sensor not only has good repeatability and high sensitivity but is capable of passive wireless detection.
使用无源无线传感器来检测氢气可以达到降低成本和延长使用寿命的目的，因为传感器无需电池即可工作。在本文中，通过将声表面波（SAW）标签和电阻式氢气传感器相结合，实现了一种在室温下工作的无源无线氢气 SAW 传感器。SAW 标签是在 128° YX-LiNbO3 衬底上制造的，其中心频率为 433 MHz。具有 Pt 涂层 ZnO 纳米棒作为传感膜的电阻式氢气传感器具有稳定性高、重复性好和制造简单等优点。通过水相法合成 ZnO 纳米棒，并采用 Pt 涂层作为氢气检测的催化剂。在与 SAW 标签结合之前，先对电阻式氢气传感器的性能进行了检查。结果表明，相对湿度和温度变化引起的电阻变化可以忽略不计。最后，在室温下对各种氢气浓度进行了无线配置和测量。由于氢气浓度变化引起的相对回波损耗的差异非常明显且可识别。所有的响应都表明，所提出的氢气传感器不仅具有良好的重复性和高灵敏度，而且能够进行无源无线检测。
