中文摘要：

针对传统涂敷敏感膜的声表面波（SAW）气敏传感器存在成膜困难、选择性差、重复性差以及再生性差等问题，提出了一种基于气体气液相转变效应来检测痕量挥发性有机气体（VOCs）的SAW气体传感器．建立了气液相转换效应模型，推导出传感器灵敏度与温度、有机蒸气质量分数之间的函数关系，并建立了VOCs液相凝聚层负载下的SAW波传模型，仿真计算了波传频散和波传衰减，从理论上阐释了传感器具有高灵敏度．同时引入气相色谱（GC）分离柱作为无敏感膜涂敷SAW气体传感器的选择性虚拟列阵，以解决这种高灵敏度气体传感器用于混合VOCs测量时的选择性问题．初步的实验结果表明，该传感器系统具有灵敏度高（可检测质量分数为10^-9的VOCs）、分析时间短、选择性好、微型化、成本低等优势．

英文摘要：

Due to problems of selectivity, repeatability and reproducibility, as well as the difficulty of sensitive film coating, polymer-coated surface acoustic wave （SAW） sensors have limits for application in gas detection. A novel Rayleigh SAW sensor based on the mechanism of gas-liquid phase transition on the surface of piezoelectric crystal substrate was developed to improve those limits. The model of gas-liquid phase transition effect was founded to illustrate the relationship between sensor sensitivity and temperature, gas concentration. The model of SAW propagation was deduced when a liquid thin layer induced by the condensation of volatile organic compounds （VOCs） was loaded on the surface of piezoelectric substrate. The frequency dispersal and attenuation of wave propagation were also simulated and calculated, which theoretically elucidated that the novel SAW gas sensor has high sensitivity. This polymer-uncoated Rayleigh SAW sensor integrated with gas chromatography （GC） separation column as the virtual sensors array for the selectivity, can resolve the problem of selectivity when it is used for mixed trace VOCs detection. The preliminary experimental result showed that this gas detection system has good selectivity, high sensitivity （limit of detection： wB = 10^-9）, short detection time, tiny size and low cost.