Flexible dual-mode surface acoustic wave strain sensor based on crystalline LiNbO3 thin film
Flexible dual-mode surface acoustic wave strain sensor based on crystalline LiNbO3 thin film
复制标题
基于晶体LiNbO3薄膜的柔性双模声表面波应变传感器
DOI：
10.1088/1361-6439/aaf5b7
复制
发表时间：
2019-02-01
影响因子：
2.3
通讯作者：
Luo, Jikui
中科院分区：
文献类型：
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作者：
Xu, Hongsheng;Cao, Zhen;Luo, Jikui
本文介绍了基于单晶薄膜铌酸锂（TF-LN）的柔性双模表面声波（SAW）传感器的开发。通过数值模拟研究了声表面波的传播及其对应变敏感性的影响。数值分析和实验分析了应变灵敏度随外加应变与声表面波传播方向夹角的变化规律，结果表明，最大应变灵敏度出现在45°方向，而不是纵向方向。利用微加工技术得到的128°y形切TF-LN（~50µm）作为压电衬底，制备了具有瑞利模式和厚度剪切模式的SAW应变传感器。该传感器具有出色的灵活性，并显示出卓越的能力，可进行高达±3000的超宽范围应变测量。在25°C - 100°C范围内研究了温度对谐振频率和应变灵敏度的影响，并观察到双模态的相似温度特性。介绍了一种双模式间的温度频率方法，该方法能够消除温度对应变传感的影响，具有片上温度影响消除能力。这些结果清楚地表明，该传感器在柔性电子和微系统中具有巨大的应用潜力。
This work presents the development of flexible dual-mode surface acoustic wave (SAW) sensor based on single crystalline thin film lithium niobate (TF-LN). Numerical modeling is conducted to investigate the SAW propagation and the effects on strain sensitivity. The dependence of strain sensitivity on angles between the applied strain and SAW propagation direction is analyzed numerically and experimentally, showing that the maximum strain sensitivity is at 45° rather than longitudinal direction. 128° Y-cut TF-LN (~50 µm), obtained by micromachining technique, is utilized as the piezoelectric substrate to fabricate the SAW strain sensors with dual-mode, namely Rayleigh mode and thickness shear mode. The sensor has excellent flexibility and demonstrates remarkable capability for an ultra-wide range strain measurement up to ±3000 . Temperature effects on resonant frequency and strain sensitivity are investigated in the range of 25 °C–100 °C, and similar temperature characteristics are observed for the dual modes. A method of beat frequency between the dual modes is introduced which is able to eliminate the temperature effect on strain sensing, an on-chip temperature influence removing capability. All the results clearly show that this sensor exhibits great potential for applications in flexible electronics and microsystems.