Transmission line analysis on high-speed digital interconnection

The author introduces a simple transmission line theory for the rectangular coaxial line and demonstrates a method for calculating both the characteristic impedance and the attenuation constant. A finite-difference method is shown to obtain the electric potential and field surrounding the conductor, which are necessary to calculate the parameters. The derived formulas are easily incorporated in software for any desktop computer. It is noted that desktop CAD (computer-aided design) of this sort can be not only a benchmark for evaluating more sophisticated CAD software but also a guide for understanding the fundamental electrical design issues of the high-speed interconnection.<>