带有覆盖介质层的微带线的特性分析

Characteristic Analysis of Microstrip Line with a Dielectric Cover

本文从麦克斯韦方程出发,通过付里叶变换和坐标旋转,导出特征坐标系中谱域场表达式.利用场匹配技术,建立起TE^z真和TM^z模的等效传输线网络,使场问题转化为网络问题,简化了特征方程的推导。然后,运用谱域导抗法具体分析由单轴介质构成的带有覆盖介质层的微带线的特性,根据有效介电常数和特征阻抗的数值结果,得出了在宽带情况下,用标准微带线的综合公式近似代替能得到较高精度的结论,这对设计电磁耦合带馈式微带天线阵的馈线极为有用。

The spectral-domain field expansions are derived from Maxwell's equations by using the Fourier transform and a coordinate rotation. In this paper,an equalivalent circuit between TEz and TMz modes has been set up by the mode match technique. Thus the field is transformed into a network problem,which makes the deduction of the characteristic e-quation simpler. The properties of covered microstrip line,made of an uniaxially anisotropy media, have been analyzed in detail, using the spectral-domain immittance approach. Following the numerical results of the effective dielectric constant and characteristic impedance,when the strip is wide,it is reasonable to obtain the high accuracy by the approximate replacement of the standand microstrip line formula,which is very useful in the design of feedlines in the electromagnetically coupled strip-fed microstrip antenna arrays.