高阶S_(21)拟合策略在耦合矩阵提取方法中的运用  

Application of the high-order S_(21) fitting strategy in coupling-matrix-extraction methods

作　　者：谢晗宇 吴边[1] 杨毅民 赵雨桐 程英鑫 陈建忠 苏涛[1] XIE Hanyu;WU Bian;YANG Yimin;ZHAO Yutong;CHENG Yingxin;CHEN Jianzhong;SU Tao(School of Electronic Engineering,Xidian University,Xi’an 710071,China;School of Artificial Intelligence,Xidian University,Xi’an 710071,China)

机构地区：[1]西安电子科技大学电子工程学院,陕西西安710071 [2]西安电子科技大学人工智能学院,陕西西安710071

出　　处：《西安电子科技大学学报》2024年第4期15-28,共14页Journal of Xidian University

基　　金：国家重点研发计划(2021YFA1003400);国家自然科学基金(62171348,62071357,U19A2055)。

摘　　要：对测试或仿真得到的采样数据进行有理函数拟合是滤波器耦合矩阵提取方法的重要一步,针对拟合数据与采样数据在幅度值较小的传输零点附近偏差较大的问题,提出一种高阶传输系数(S_(21))拟合策略。该策略通过对采样的传输系数使用具有N阶(N为滤波器阶数)分子多项式的有理函数进行拟合以提高拟合准确度,从而准确定位传输零点。然后从N个拟合得到的传输零点中选取N_(z)个(N_(z)为实际滤波器的传输零点个数)有效传输零点重构传输系数的分子多项式,以保证提取的耦合矩阵的传输零点个数与实际滤波器相同。为验证效果,使用具有三个传输零点的九阶同轴滤波器对传统柯西方法、应用高阶传输系数拟合策略的柯西方法与基于模型的矢量拟合方法(MVF)进行试验,结果显示应用了该策略的柯西方法相较于传统柯西方法与MVF可以提高传输零点的拟合准确度。由于柯西方法对噪声的健壮性不高,最后结合柯西方法与MVF的步骤,提出一种通过矢量拟合定位S参数零点的耦合矩阵提取方法,该方法相较于MVF可以更加精确地拟合上S参数的零点,同时相较于柯西方法对噪声的抗性更好。Fitting the measured or simulated sampled data by a rational function model is an important step in a filter coupling-matrix-extraction method.A high-order transmission coefficient(S_(21))fitting strategy is proposed to address the problem of the deviation between the fitted and sampled data near the transmission zeros with small amplitudes.This strategy achieves a high fitting accuracy by fitting the sampled transmission coefficient with a rational function with a numerator polynomial of N th-order(N being the order of filter)to accurately locate the transmission zeros.Then,the numerator polynomial of the transmission coefficient is reconstructed by selecting the N_(z)(N_(z) being the number of transmission zeros of the real filter)desired transmission zeros among the N fitted transmission zeros to guarantee that the number of transmission zeros of the extracted coupling matrix is the same as that of the real filter.For verification,a ninth-order coaxial filter with three transmission zeros is used as an example to validate the conventional Cauchy method,the Cauchy method that applies the higher-order transmission coefficient fitting strategy,and the model-based vector fitting method(MVF).The results show that this strategy can improve the fitting accuracy near the transmission zeros.Since the robustness of the Cauchy method is not high enough,a coupling-matrix-extraction method by identifying the zeros of S-parameters using vector fitting is proposed in this paper by consisting the operation steps of the Cauchy method and MVF,this method can fit the zero of S-parameters more accurately than MVF and has a less influence by noise than the Cauchy method.

关 键 词：微波滤波器 等效电路 耦合矩阵提取 柯西方法 矢量拟合方法 

分 类 号：TN713.5[电子电信—电路与系统]