低损耗宽带声表滤波器  

Wideband Low Loss SAW Filter

作　　者：陈慧[1] 王宁[1] 林基明[1] 吴浩东[1] 水永安[1] 

机构地区：[1]南京大学现代声学国家重点实验室,声学研究所,南京210093

出　　处：《压电与声光》2002年第5期343-345,共3页Piezoelectrics & Acoustooptics

基　　金：国家自然科学基金资助项目 (10 0 740 3 40)

摘　　要：移动通信需要低损耗高性能的单相单向换能器 (SPU DT) ,其设计常采用变指宽来实现 ,但目前的设计水平还很难满足需求。基于耦合模式模型理论 ,采用优化算法 ,寻找到最佳的单胞结构 ,使每个单元的反射率超过 5 %。利用这样的单胞所构成的滤波器频带宽 ,面积小 ,性能远优于当前水平的滤波器。用不加权的 19个单相单向换能器单元构成滤波器 ,其实测单向性达到 19d B,3d B的带宽为 4 %～ 5 % ,插损 3.1d B。实验证实 SPUDT单胞优化是可以做到的 ,从而大大改善了滤波器性能。Single Phase UniDirection Transducer(SPUDT)with high specifications is widely used in mobile communications.Most of them are constructed by EWC SPUDT.But the design level doesn't satisfy with the requirement.On the basis of coupling of modes(COM)theory we find an optimized EWC/SPUDT structure under which the reflectivity could be more than 5%.A filter in such structure has wider band,smaller size,and much better performance than those of present products.Using 19 SPUDT cells without weighting,we set up a wideband low loss filter.The measured bandwidth is 4%～5% and the insertion loss is 3.1 dB.The experimental results verify the theory,and show the optimization of SPUDT structure is possible so as to improve the filter greatly.

关 键 词：低损耗宽带滤波器 电极宽度控制 单相单向换能器 反射率 移动通信 SPUDT 

分 类 号：TN929.5[电子电信—通信与信息系统] TN713[电子电信—信息与通信工程]