低损耗乐甫波传感器的实验研究  

Experimental Research of Low-loss Love Wave Sensors

作　　者：程利娜[1] 刘明华[1] 李红浪[1] 何世堂[1] 

机构地区：[1]中国科学院声学研究所,北京100190

出　　处：《仪表技术与传感器》2009年第B11期123-124,174,共3页Instrument Technique and Sensor

基　　金：国家自然科学基金项目(10774159)

摘　　要：文中采用单相单向叉指换能器(SPUDT)降低乐甫波传感器的双向损耗,并从实验方面研究了SPUDT结构反射中心位置对器件损耗的影响。乐甫波传感器的多层波导结构改变了常规的EWC/SPUDT(控制栅条宽度的SPUDT)的反射系数和换能系数,不能实现完全的单向传播,从而使传感器损耗变大。文中通过调整反射栅的位置,来改变反射中心和换能中心的间距L,通过实验的方法分析L对损耗的影响,得到了间距L与器件损耗之间的关系。文中实验基片采用ST-90°X石英,铝电极厚度为0.77%λ(λ为SPUDT周期),声波导材料为二氧化硅,厚度为0.0128λ,L大小范围为(3/8-1/9)λ到(3/8+1/9)λ,实验结果表明:随着反射中心和换能中心间距L的增大,器件中心频率处的损耗从20.2 dB减小到12.5 dB;器件的单向性能得到改善。Single phase unidirectional transducer （SPUDT） was introduced to reduce bidirectional loss for Love wave sensors in this paper. An experimental research is simultaneously performed to study the relation between location of the reflection center and device＇ s insertion loss. Love wave, a waveguide mode, usually propagates in the multi-layered structure, which deteriorates the pure single direction of traditional EWC/SPUDT （ Electrode width controlled SPUDT）, and decreases device＇ s insertion loss. This paper firstly changes the relative distance （L） between transduetion center and reflection center. The variable L is used to find a suitable value to deduce insertion loss. Then, an experimental analysis is given for a relation between L and insertion loss. As an example, a substrate used in this paper is ST -90°X cut quartz, and the thickness of A1 electrode is about 0.77% of wavelength （A）. The guiding layer is silicon dioxide, while the distance L is between （3/8 - 1/9 ）λ and （3/8 ＋ 1/9）λ. In conclusion, as the increasing of the distance L, Love wave sensor＇s insertion loss at center frequency decreases from 20. 2 dB to 12. 5 dB, while meliorating sensor＇s unidirectional character.

关 键 词：乐甫波传感器 单相单向结构 损耗 

分 类 号：TP212[自动化与计算机技术—检测技术与自动化装置]