利用形变媒质上小振幅声波理论研究石英基板上声表面波温度特性(英文)  

Investigation of temperature characteristics of surface acoustic waves on quartz substrates by using theory of small amplitude vibrations in deformed media

作　　者：罗中涌 曹明 公勋 章德 

机构地区：[1]近代声学教育部重点实验室,南京大学声学所,南京大学物理学院声科学与工程系,南京210093

出　　处：《南京大学学报（自然科学版）》2013年第1期52-57,共6页Journal of Nanjing University（Natural Science）

基　　金：National Natural Science Foundation of China(10974094)

摘　　要：对于声表面波而言温度特性是非常重要的一个指标.而石英基板在表面波器件中应用广泛.当环境温度改变时,基板尺寸会发生变化,弹性系数和压电系数值也会发生变化,在考虑这些变化的基础上就可以考察声表面波器件的温度特性.这是通常的方法.但是,弹性系数和压电系数的温度系数其实参考了随温度变化的中间状态,而并非定义弹性系数和压电系数的参考温度时的状态.在某些场合下,由于温度变化会产生一个非均匀分布的形变,比如带电极的体波谐振器以及多层声表面波基板,上述方法就会失效.在其它的一些场合,如力和加速度传感器的情况,初始形变可能是由于外力或者加速度造成的.为了得到这些在形变媒质上小振幅声波的传播特性,一些学者从非线性方程发展出一套理论.按照这种理论,可以得到参考同一参考状态的弹性常数以及它们的温度系数.P.C.Y.Lee和Y.K.Yong[Journal of Applied Physics,1986,60:.2327]给出了一套完整的热形变媒质中小振幅振动的理论,并推导出了石英晶体弹性常数的一阶、二阶和三阶温度系数.他们成功地考察了石英体波谐振器的温度特性.在本文中,我们对LeeandYong的理论加以推广,引入了压电性.这样,该方法也可以用来分析具有强压电性的基板了.我们分析了石英基板上声表面波的温度特性.文中给出了ST-切,MD-切和K-切石英基板的计算结果.计算结果证明了该方法的有效性.当然新方法比传统的方法要复杂的多.因为该方法在理论上具有一般性,如果先计算出器件结构中初始应变的分布,它就可以顺利地来分析多层基板上声表面波或者是一些传感器的工作特性.The temperature characteristics are important for surface acoustic wave （SAW）devices. And quartz substrates are very popular for SAW application. Conventionally, when temperature characteristics of SAW are in vestigated, the dimensional change due to environmental temperature change is first considered and then the temperature derivatives of the elastic and piezoelectric constants are introduced to analyze it. However,the used tem- perature derivatives of the effective elastic constants are referred to the variable temperature-dependent intermediate state rather than the fixed reference state, to which the fundamental elastic constants are referred. The conventional method cannot conveniently be employed because temperature change usually leads to initial inhomogeneous strain distribution in the device structure. P. C. Y. Lee and Y. K. Yong have given a complete set of theory for small amplitude vibrations in thermally deformed media. They have successfully applied their theory to investigate the temperature characteristics of bulk wave resonators of quartz. In this paper,their work is further extended to include the piezoelectricity. The temperature characteristics of SAW on quartz plates are investigated hy using the new method. For the generality of the present method, given calculated first, the new method is ready for analyzing the the initial strain distribution in the device structure is multilayered SAW substrate or sensors.

关 键 词：石英基板 声表面波 温度特性 

分 类 号：TN65[电子电信—电路与系统]