On the Accuracy of the Parameters Extracted From $S$-Parameter Measurements Taken on Differential IC Transmission Lines

Abstract

In this paper, we compare the accuracy of the telegrapher's equation transmission line parameters extracted with different methods from deembedded <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">S</i> -parameter measurements taken on differential integrated circuit transmission lines. We present a mathematical proof that conventional ldquoopen-shortrdquo deembedding is sufficient to extract the intrinsic propagation constant gamma of the transmission line, but that at the same time, some deembedding errors will remain for the extracted characteristic impedance <i xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">Z</i> <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">0</sub> . We illustrate this by comparing experimental results obtained after ldquoopen-shortrdquo and ldquoshort-openrdquo deembedding, and explain that as a result of this, using either known capacitance/known conductance or known inductance/known resistance approximations to study the remaining transmission line parameters can be attractive.