声表面波单指无内反射叉指换能器结构及其性能分析

The Structures of SAW Single-electrode IDT without Internal Reflection and the Analysis on Their Properties

根据我们以前的理论,本文提出了一些常用晶体的各种可能的单指无内反射叉指换能器结构,并分析了影响它们性能的几种因素。其中YZ—LiNbO_3,ST—X石英及X,112°YLiTaO_3上的金或金加铬单指结构存在某些缺点,用途受到较大限制,仅适用于带宽较宽及对中心频率准确度要求不太严格的场合。而上述三种基片上的沟槽填铝结构及Y128°LiNbO_3的铝和铝加铬单指结构是比较好的结构,具有比较广泛的用途。最后给出了我们在ST—X石英上用沟槽填铝单指结构研制的一种高带外抑制窄带滤波器的实验结果。

From, our previous theory[1], this paper proposed several probable ctures of single-electrode IDT without internal reflection on the usual crystals , and analyzed the factors affecting their properties.Among these, the Au and Au-Cr single-electrode IDT on YZ-LiNbOa, ST-X quartz and X-H2Y LiTaO3 plates have some defects and their, uses are limited, only suitable to wide bandwidth as well as the field required mid-frequency not precisely.The Al-buried-groove-single-electrode structure on the three fcmdsof crystal plates mentioned above and the structures of Al and Al-Cr single-electrode are better, and have wide applications.Finally,the paper showed the experimental results of a narrow band filter with high outband suppression, which is developed using Al-buried-groove-single-electrode structure.