混合谱域法分析微屏蔽线特性阻抗的频率特性

微屏蔽线是一种新型的微波集成电路传输线，可应用于亚毫米波段，作为一种准平面传输线，微屏蔽线很难用一般谱域法进行一波分析，应用改进的谱域法－混合谱域法对微屏蔽线进行全波分析，导出了微屏蔽线特性阻抗的计算公式，并对一些特定尺寸的微屏蔽线进行了数值计算。计算结果表明，微屏蔽线的阻抗变化范围很宽。另外，微屏蔽线还具有极宽的准静态带宽，但在亚毫米波段其特性阻抗变化较大，讨论了屏蔽腔宽度对微屏蔽线特性阻抗频率特性的影响，减小屏蔽腔的宽度可以拓宽微屏蔽线的工作带宽。混合谱域法运算量较小，精度较高，是一种用来分析准平面传输线的有效方法。

Fullwave Analysis of Frequency Dependence of Microshield Line Characteristic Impedance by Mixed Spectral Domain Approach

The microshield line,a new type of monolithic planar transmission line,is investigated analytically.Its features in comparison with other conventional planar lines are highlighted.The characteristic impedance of the microshield line is obtained by using the mixed spectral domain approach.The analytical expressions of the characteristic impedance are derived.The numerical results show the frequency dependence of the characteristic impedance.In addition,The microshield line is a wide band transmission line whose characteristic impedance varies greatly in sub millimeter band.The effect of the shield cavity width on the frequency dependence of the characteristic impedance is demonstrated.Reduction of the width of the shield cavity can broaden the working band of the microshield line.It is shown that the mixed spectral domain technique is a powerful, accurate, numerically efficient approach for analysis of quasi planar transmission line structures.