应用史密斯圆图提取慢波微带线特征阻抗方法

Novel method of extracting characteristic impedance of slow-wave microstrip using Smith chart

慢波微带线的多种不连续性和相邻慢波单元的耦合影响了特征阻抗的准确计算,因此在慢波微带线的设计阶段需要一种手段来提取其特征阻抗。提出一种利用史密斯圆图提取慢波微带线特征阻抗的方法,该方法通过观察慢波微带线的反射系数在史密斯圆图中的图像估计其特征阻抗的大小,并通过反射系数极值计算特征阻抗。以梳状慢波微带线为例检验该方法,特征阻抗的提取结果与利用S参数提取的结果十分接近,从而证明该方法是一种可行的慢波微带线特征阻抗提取方法。

The various discontinuities of slow-wave microstrip and coupling of adjacent slow-wave units make the accurate calculation of characteristic impedance difficult,thereby an extracting method is needed highly in the designing process of slow-wave microstrip.Introduces a novel method of extracting characteristic impedance of slow-wave microstrip.The method estimates the characteristic impedance of slow-wave microstrip by observing the curve of reflection coefficient on Smith chart,a calculation formula of characteristic impedance is provided also.A comb-like slow-wave microstrip line is designed to justify the method,the extracted characteristic impedance and the ones from S parameters are very approximate,which justifies the extracing method an applicable one.