一种改进的微波滤波器调试方法

An improved computer-aided tuning method for microwave filters

传统滤波器诊断调试方法通过提取滤波器等效电路参数与理想参数对比来决定调试方向,并未考虑调谐元件之间的相互耦合关系且未考虑调试幅度的大小,因而调试效率低下。为解决这一问题,提出一种基于遗传算法与渐进空间映射算法相结合的计算机辅助调试方法。利用遗传算法优化得到滤波器输入输出端的相移长度,去除相移后利用柯西法对滤波器进行参数提取,通过渐进空间映射算法确定滤波器调谐元件的调试方向与幅度,从而使微波滤波器快速达标。采用该方法对四阶交叉耦合滤波器进行调试,仅通过4次迭代即可使滤波器达标,验证了该提出方法的有效性与准确性。

The traditional diagnosis and tuning method for microwave filter only extract, the equivaient circuit parameters, butnot the tuning magnitude. The couplings between the tuning elements are not considered, and it is very inefficient. In order to di-agnos and tune the microwave filter quickly, we must determine the tuning direction and value. An improved tuning method basedon genetic algorithm and aggressive space mapping is presented in this paper. The measured or simulated parameters such as Sparameters are not suitable for parameter extraction directly. The phase shift effect must be removed before parameter extraction.The phase shift effect is moved by using the genetic algorithm. The equivalent circuit parameters are extracted through Cauchymethod after the phase shift effect is removed. The tuning direction and value are determined by aggressive space mapping, whichmakes the filter meet the specifications. A fourth order cross-coupled filter tuning example is used to verify the new method andshows the validity of the method. The filter meets specifications less than four iterations. The method presented in this paper canbe applied to other type filter diagnosis and tuning.