As the data rate and density of digital high-speed systems are getting higher, far-end crosstalk (FEXT) noise becomes one of the major issues that limit signal integrity performance. It was commonly believed that FEXT would be eliminated for strip lines routed in a homogeneous dielectric, but in reality, FEXT can always be measured in strip lines on the fabricated printed circuit boards. A slightly different dielectric permittivity (ϵr) of prepreg and core may be one of the major contributors to the FEXT. This article is focusing on providing a practical FEXT modeling methodology for strip lines by introducing an approach to extract ϵr of prepreg and core. Using the known cross-sectional geometry and measured S-parameters of the coupled strip line, the capacitance components in prepreg and core are separated using a two-dimensional solver, and the ϵr of prepreg and core is determined. A more comprehensive FEXT modeling approach is proposed by applying extracted inhomogeneous dielectric material information.


Electrical and Computer Engineering


National Science Foundation, Grant IIP-1440110

Keywords and Phrases

Dielectric material; Far-end crosstalk (FEXT); Stripline; Transmission-line theory

International Standard Serial Number (ISSN)

1558-187X; 0018-9375

Document Type

Article - Journal

Document Version

Final Version

File Type





© 2023 Institute of Electrical and Electronics Engineers, All rights reserved.

Publication Date

01 Feb 2022