针对液体流速测量领域中微型流量传感器高品质因数、高灵敏度的性能要求。本文设计一种双端增强型薄膜谐振结构实现Lamb波传感器的高品质因数, 利用传感器反对称模式(A01模式)在薄膜-液体界面处的消逝波实现液体流速矢量测量。所制作的双端增强型薄膜谐振Lamb传感器A01模式的主峰品质因数为703, A01模式的频率移动量与液体流速大小存在线性关系, 频率移动方向与液体流动方向存在对应关系。流速实测灵敏度约为270 Hz/mm/s, 传感器稳定性噪声小于02 Hz, 流速最低检测极限值(LOD)为2.2 μm/s, 流量最低检测极限值(LOD)为18.3 nL/min。结果表明, 双端增强型薄膜谐振Lamb波传感器可以实现液体流速高灵敏度矢量测量。

The trend of further research of the micro flow sensor is higher quality factor and sensitivity in the field of velocity measurement. In this letter, a new type of double-ended enhanced film resonance structure was proposed to obtain high quality factor of the Lamb wave sensor. The vector measurements of the liquid flow velocity can be achieved by using the evanescent wave, which exists around the membrane-liquid interface of one antisymmetric mode(A01) of this Lamb wave sensor. The quality factor for the prominent peak of the A01 mode reaches 703. There is a linear relationship between the phase frequency shifts of A01 mode and the value of fluid velocity, while the direction of flow velocity can be judged by the phase frequency shifts direction. Correspondingly, the sensitivity of flow velocity measurement is about 270 Hz/mm/s. As the maximum noises of A01 mode is less than 02 Hz, the limit of detection of the flow velocity(LOD) is 2.2 μm/s and the flow rate(LOD) is 18.3 nL/min. The results demonstrate that the vector measurements of the liquid flow velocity can be actualized with high sensitivity by the double-ended enhanced Lamb wave sensor.