雙芯纜線(twinax cable)常被用於印刷電路板(Printed Circuit Board, PCB)與
印刷電路板的連接媒介，長度介於十公分至一公尺，由於纜線於製造上的誤
差，使得纜線在橫截面無法完全對稱，又對於較長的纜線，截面結構不對稱
是可能會發生要保持纜線內部完全對稱，對於截面結構不對稱纜線對於混合
模態 S 參數的影響目前較少文獻在討論。
本論文將使用傳輸線法分析雙芯纜線於截面結構不對稱情況下，纜線內
部的變化，並通過對雙芯纜線的各項參數進行參數以取得纜線各項參數對於
混合模態 S 參數的影響，最後透過量測來驗證理論並確認目前工廠製程的製
造最大偏移是否能符合規範。

Twinax cables are commonly used as a connection medium between Printed
Circuit Boards (PCBs). Their lengths typically range from ten centimeters to one meter.
Due to manufacturing tolerances, the cables cross-sections are not completely
symmetrical, especially for longer cables. The impact of asymmetrical cross-sectional
structures on the mixed-mode S-parameters of the cables has received limited attention
in current literature.
iii
This paper aims to analyze the internal variations of twinax cables under asymmetrical
cross-sectional structures using the transmission line method. By examining the
parameters of the twinax cables, the study will determine the influence of these
parameters on the mixed-mode S-parameters. Finally, measurements will be conducted
to validate the theory and confirm that the maximum manufacturing deviation in the
current factory process complies with specifications such as PCIe Gen6.

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