基于阻抗匹配的电子标签式香蕉气体传感器

为监测香蕉在仓储运输过程中的新鲜程度,研制了一款电子标签式香蕉气体传感器。该传感器由标签天线和气敏薄膜两部分构成。利用电磁仿真软件,设计了谐振频率为915 MHz的领结型标签天线。通过多种气敏材料的复阻抗对比,选取多壁碳纳米管(MWNTs)为气敏材料,并掺杂少量导电碳浆对其进行降阻,解决了传感器气敏薄膜同标签天线之间的阻抗匹配问题。搭建气敏测试平台,测试了传感器对不同时期香蕉释放气体的响应特性。实验结果表明,标签气体传感器对香蕉释放气体具有良好的响应和恢复特性;当香蕉分别处于新鲜期、成熟期和腐烂期时,对应的传感器谐振频率变化Δf_c分别为9、36和18 MHz,可实现香蕉新鲜程度的定性识别。

Electronic tag type banana releasing gas sensor based on impedance matching

In order to monitor the freshness of banana in the process of storage and transportation, an electronic tag type banana releasing gas sensor which includes tag antenna and gas sensitive film is designed.At resonance frequency of 915 MHz, a bow-tie tag antenna is designed with electromagnetic simulation software.The multi-walled carbon nanotube is selected as the gas sensitive material by comparing the complex impedance of five kinds films.With the incorporation of a small amount of conductive carbon paste, the impedance regulation of the gas-sensitive film is successfully resolved, and the impedance matching between the antenna and the gas sensor is achieved.The gas sensitive testing platform is established to test the response characteristic of the sensor for banana releasing gas at different maturity.The experimental results indicate that the tag gas sensor has a good response and recovery characteristic for banana releasing gas.The resonant frequency change of sensor is 9, 36, 18 MHz when banana is in fresh, ripe, and rotten period respectively.Therefore, the freshness of banana can be qualitatively identified.