声表面波滤波器的匹配电路设计

Design of SAW Filter Matching Circuit

介绍了通过测试仪器采集的声表面波(SAW)滤波器的Sij(i,j=1,2)参数来优化匹配电路的方法。首先将采集的Sij(i,j=1,2)参数转换为SAW滤波器Yij(i,j=1,2)参数,然后建立新的S12(或S21)参数与匹配电路的依赖关系,通过优化匹配电路元件值,而使滤波器的插入损耗和通带波动满足目标值,该方法的主要优点是考虑整个通带特性,而不是考虑通带内的某一点(如中心频率)。

Sij(i,j=1,2) parameter is used to optimize the matching circuit in this paper.Firstly Sij is converted to the Yij(i,j=1,2) parameter of SAW filter,then a new independence between S12(or S21) and matching circuit is established.The target insertion loss and passband ripple are obtained by optimizing the matching circuit component value.The advantage of this method is the full consideration of the whole passband,but not just certain point (i.e.:center frequency) in the passband.