高矩形度低损耗梯形SAW滤波器设计  

High Rectangularity and Low Loss Trapezoidal SAW Filter Design

作　　者：张昆 王红亮[1] ZHANG Kun;WANG Hongliang(State Key Laboratory of Dynamic Testing Technology,North University of China,Taiyuan 030051,China)

机构地区：[1]中北大学省部共建动态测试技术国家重点实验室,山西太原030051

出　　处：《压电与声光》2024年第6期878-883,共6页Piezoelectrics & Acoustooptics

基　　金：山西省基础研究计划项目(20210302123034)。

摘　　要：为了确保5G时代不同物联网设备之间中频波段频谱隔离,设计了一款基于瑞利波模式的高矩形度、低损耗梯形声表面波(SAW)滤波器。该滤波器采用Al电极,压电材料为128°YX-LiNbO_(3)。为实现低损耗的设计要求,通过有限元法仿真分析了电极厚度、占空比、孔径和反射栅对谐振器性能的影响。同时,为了抑制通带内杂散,采用了一种非标准短路栅结构。为改善普通拓扑结构滤波器通带两侧的波纹问题,设计了一种新型镜像拓扑结构,通过减小滤波器的电容比(C_(0p)/C_(0s))达到实现高矩形度的设计目标。最终设计出一款中心频率315.03 MHz,-3 dB带宽11.62 MHz,最小插入损耗0.758 dB,带外抑制35.931 dB,矩形系数1.30的六阶梯形SAW滤波器。In this study,a high rectangular and low loss trapezoidal SAW(Surface Acoustic Wave)filter based on Rayleigh wave mode is designed to ensure the spectrum isolation of the mid-frequency band between different IoT devices in the 5G era.The electric electrode of the filter is the Al electrode,and the piezoelectric material is 128°YX-LiNbO_(3).To realize the design requirement of low loss,the influence of electrode thickness,duty cycle,aperture,and reflector gate on the resonator performance is simulated by the finite element method.Simultaneously,a non-standard short-circuit gate structure is adopted to suppress the spurious in the passband.A new image topology is designed to improve the waviness on both sides of the passband of general topology filters.Furthermore,the design goal of high rectangularity is achieved by reducing the capacitance ratio of the filter(C_(0p)/C_(0s)).Finally,a six-step SAW filter with a center frequency of 315.03 MHz,-3 dB bandwidth of 11.62 MHz,minimum insertion loss of 0.758 dB,out-of-band rejection of 35.931 dB,and rectangular coefficient of 1.30 is designed.

关 键 词：高矩形度 低损耗 有限元法 非标准短路栅 电容比 梯形SAW滤波器 

分 类 号：TN713[电子电信—电路与系统]