Abstract

The surface acoustic wave (SAW) sensor has been widely used to measure torque, and the temperature effect on torque sensitivity has been taken into account. However, few studies have been devoted to the influence of electrode on the torque sensitivity. In order to design a SAW torque sensor with high performance, it is necessary to analyze the effect of electrode. We adopt the Mindlin’s thin plate equations as a boundary condition due to the electrode, propose a method to evaluate the effect of electrode and make a comparison between our calculation and experimental results. Then, we obtain the frequency shifts with different electrode materials when the applied torque is zero. Finally, we evaluate the torque sensitivity with the effect of electrode and obtain the result with the errors about 1.7 and 7.6% compared with experimental data. The errors have been improved greatly with respect to the calculation ignoring electrode effect, about 30%. However, the analysis is valid only under the condition that the thickness of electrode is relatively small, which is satisfied in the general conditions.

中文翻译：

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电极膜对声表面波转矩灵敏度影响的分析与评估

摘要

表面声波（SAW）传感器已被广泛用于测量扭矩，并且已经考虑了温度对扭矩灵敏度的影响。然而，很少有研究致力于电极对转矩灵敏度的影响。为了设计高性能的SAW扭矩传感器，必须分析电极的作用。我们将Mindlin薄板方程式作为电极的边界条件，提出了一种评估电极效果的方法，并对我们的计算结果和实验结果进行了比较。然后，当施加的扭矩为零时，我们获得了不同电极材料的频率偏移。最后，我们通过电极的作用来评估扭矩灵敏度，并获得与实验数据相比误差约为1.7和7.6％的结果。相对于忽略电极效应的计算，该误差已大大改善，约为30％。但是，该分析仅在电极的厚度相对较小的条件下才有效，这在一般条件下是可以满足的。