短截线阻抗匹配器设计的优化解决方案

由于传输线阻抗变换公式的复杂性,一般情况下不能直接使用它进行短截线阻抗匹配器的设计。为此提出了一种根据阻抗变换公式构造目标函数,通过求极值的方法解出短截线的位置,进行短截线阻抗匹配器设计的方案。为了克服这个目标函数固有的周期性,非凸性和多值性,对所采用的线性分式插值进行了改进,从而保证了极值的快速收敛。在此基础上开发了一个用于设计短截线阻抗匹配器的程序,它完全可以取代传统的施密特圆图法。给出了这个程序的准代码和设计实例。实验结果表明,采用此方法整个设计过程可以在30 s内完成,速度和精度远远超过传统的设计法。

Optimization Solution to Stub-Tuner Design

Because of the complexity of the impedance transformation formula of transmission lines,the formula could not be used directly to design the single-stub tuner.An optimization method is adapted by constructing an objective function from the impedance transformation formula,finding the minimum value and determining the location of the shunted stub.However,the objective function is periodic,non convex and has multiple solutions.In coping with this situation,a linear fractional interpolation algorithm is improved and a fast convergence is guaranteed.A program for stub tuner design is developed with which the traditional Smith chart method can be replaced for the design purpose.The pseudo code of the program and the design examples are presented.Test results show that the whole design process of this method is finished within half minute,much fast and accurate than the traditional method.