Frequency Domain Analysis of Lossy and Non-Uniform Twisted Wire pair

In the study of the frequency domain crosstalk for twisted pair, the traditional alternating inversion model is often built under the ideal condition of lossless and uniform media, ignoring the length of the twisted section. This paper focuses on the impact of these non-ideal conditions on crosstalk, applying the cascaded transmission line theory of Paul and McKnight to predict near-end crosstalk (NEXT) of two pairs of twisted wire pair (TWP) which are placed above a perfectly conducting ground or in a cylindrical ideal conductive shell. This paper put forward the non-uniform-media layered connection method (NLCM) to solve the parasitic parameter matrix, taking two layers as an example. Based on the deduced chain parameter matrix and boundary conditions, the exact crosstalk solution is obtained. All theories in this paper are of great significance to the EMC design of high-speed data transmission systems, providing the theoretical support for predicting NEXT within each device or system.