Computer-aided characterization of TEM transmission lines

A method of characterizing a multiconductor transmissionline system, which supports transverse-electromagnetic (TEM) waves traveling at different velocities, has been developed. The method combines equivalent circuit concept and optimization search technique. It is shown that the coupled transmission-line parameters can be computed from a set of wave velocities and transformer ratios that characterize the decoupled equivalent network of the multiconductor system. A combination of the steepest descent and Fibonacci-search algorithms for determining the wave-propagation velocities from frequency-domain measurements has been formulated, along with an alternative method of computing the inductance parameters from the measured characteristic admittances and static capacitances. For illustration, numerical examples and experimental results are given.