谐振式检测器指条厚度对质量型声表面波传感器灵敏度的影响  

Influence of electrode thickness of a resonance detector on the sensitivity of a mass-loading surface acoustic wave sensor

作　　者：郝文昌 王藉秋 刘久玲[1] 刘明华[1] 梁勇[1] 何世堂[1] HAO Wenchang;WANG Jiqiu;LIU Jiuling;LIU Minghua;LIANG Yong;HE Shitang(Institute of Acoustics, Chinese Academy of Sciences Beijing 100190;Jiangnan Shipyard (Group) Co.,LTD. Shanghai 201913)

机构地区：[1]中国科学院声学研究所,北京100190 [2]江南造船(集团)有限责任公司,上海201913

出　　处：《声学学报》2019年第3期385-392,共8页Acta Acustica

基　　金：国家自然科学基金项目(11304348)资助

摘　　要：研究了谐振器指条厚度对质量型声表面波传感器灵敏度的影响.利用耦合模方程推导出耦合模参量与周期栅阵禁带边界频率的关系,结合有限元及P矩阵模型,获得了声表面波传感器灵敏度随指条厚度的变化关系。制备3种不同铝指条厚度(1600?,1900?,3100?)的声表面波谐振器,通过对其表面中心区域沉积SiO_2层验证了计算结果。结果表明:采用ST-X石英基底的声表面波谐振器对SiO_2负载检测时,传感器的灵敏度随铝指条厚度的增加先变大后减小,最优归一化指条厚度为1.9%。分析表明,指条厚度对传感器灵敏度的影响主要来自于传播速度和耦合系数的共同作用,通过优化指条厚度的方法可改善传感器的灵敏度.The influence of the resonance detector’s electrode thickness on the sensitivity of a mass-loading Surface Acoustic Wave(SAW) sensor was studied. By using the Coupling-Of-Modes(COM) equations, the relationship between the COM parameters and the band-edge frequencies of periodic gratings was deduced. Combining the Finite Element Method(FEM) and the P-matrix model, the variation curve of SAW sensors’ sensitivity with the electrode thickness was obtained. The SAW resonators with three different electrode thicknesses of 1600 A, 1900 A and 3100 A were fabricated.By depositing a SiO2 layer onto the surface center area of the resonator, the theoretical results were verified. The results show that using a SAW resonator incorporating the ST-X quartz substrate to detect the SiO2 mass-loading, the sensor sensitivity increases at first then decreases with the increasement of electrode thickness. And the optimal normalized electrode thickness is 1.9%. The influence is the result of the propagation velocity and the coupling coefficient. By using the method of optimizing the electrode thickness, sensors’ sensitivity is improved.

关 键 词：声表面波谐振器 传感器灵敏度 质量型 厚度 检测器 谐振式 SiO2层 方程推导 

分 类 号：TP212[自动化与计算机技术—检测技术与自动化装置]