In this article, the coupling between the inner conductor and the shield of a coaxial cable is summarized with different coupling directions and shielding grounding conditions. An internal and external transmission line (IETL) transfer matrix is proposed to validate this coupling relationship. The induced voltage and current of the IETLs can be more intuitively represented by the IETL transfer matrix and the port voltage and current. By introducing the three-conductor system and the surface transfer impedance into the transmission line theory, the IETL transfer matrix representation of the transmission line equation with coupling components is obtained. Moreover, when analyzing the problems of coupling between field and transmission line, the coaxial cable can be equivalent to a bare wire by using IETL transfer matrix. According to this idea, an improved approximation method based on Hertzian dipole and a numerical method based on the finite element method algorithm are proposed to calculate the radiation of a coaxial cable and the crosstalk between a coaxial cable and a bare wire. Then, the results of the two methods are compared with the electromagnetic calculation software.

中文翻译：

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编织同轴电缆的内部和外部传输线传输矩阵和近场辐射

在本文中，总结了同轴电缆的内导体和屏蔽层之间的耦合，并给出了不同的耦合方向和屏蔽接地条件。提出了内部和外部传输线（IETL）传输矩阵来验证这种耦合关系。IETL的感应电压和电流可以通过IETL传输矩阵以及端口电压和电流更直观地表示。通过将三导体系统和表面转移阻抗引入传输线理论，获得了带有耦合分量的传输线方程的IETL转移矩阵表示。而且，当分析现场和传输线之间的耦合问题时，通过使用IETL传输矩阵，同轴电缆可以等效于裸线。根据这个想法 提出了一种改进的基于赫兹偶极子的近似方法和一种基于有限元算法的数值方法，用于计算同轴电缆的辐射以及同轴电缆与裸线之间的串扰。然后，将两种方法的结果与电磁计算软件进行比较。