低频率漂移极窄带声表面波滤波器

Extremely Narrow Bandwidth Surface Acoustic Wave Filter with Low Frequency Drift

摘要:

保密通信系统对极窄带宽声表面波滤波器需求迫切,由于声表面波滤波器属于温度敏感型器件,在极端恶劣环境温度下器件滤波频率会发生较大漂移,无法保证有用信号提取和近端噪声抑制。为满足射频系统全温应用要求,对基于石英衬底的极窄带声表面波滤波器的频率温度特性进行仿真分析,研究了电极金属膜厚和电极金属化率对器件二阶温度特性拐点的影响,并通过声表面波滤波器结构参数优化,研制出低频率漂移的极窄带声表面波滤波器。

Abstract:

Surface acoustic wave filters with extremely narrow bandwidth are urgently needed for use in security communication systems. The working frequency of the surface acoustic wave filter will drift significantly at ex tremely high or low ambient temperatures, which makes it hard for the filter to effectively extract useful signals and suppress noise in the near-passband. This study simulated and analyzed the frequency-temperature characteristics of extremely narrow bandwidth surface acoustic wave filter based on a quartz substrate and studied the effects of metal thickness and the metallization ratio of electrodes on the inflection point of the secondorder temperature characteris tic of the device. An extremely narrow bandwidth surface acoustic wave filter with low frequency drift was finally manufactured by optimizing the structural parameters.