Prepreg and Core Dielectric Permittivity (εᵣ) Extraction for Fabricated Stripline' Far-End Crosstalk Modeling


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 striplines routed in a homogeneous dielectric, but in reality, FEXT can always be measured in striplines 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 striplines by introducing an approach to extract εr of prepreg and core. Using the known cross-sectional geometry and measured S-parameters of the coupled stripline, 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

Publication Status

Early Access

Keywords and Phrases

Capacitance; Conductors; Dielectric Material; Dielectric Materials; Dielectrics; Far-End Crosstalk (FEXT); Nonhomogeneous Media; Permittivity Measurement; Stripline; Stripline; Transmission-Line Theory

International Standard Serial Number (ISSN)

0018-9375; 1558-187X

Document Type

Article - Journal

Document Version


File Type





© 2021 Institute of Electrical and Electronics Engineers (IEEE), All rights reserved.

Publication Date

10 Jun 2021