The Impact of PCB Dielectric Thickness on Signal Crosstalk


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This article studies the impact of dielectric thickness on crosstalk for transmission lines in single-ended and differential mode on outer (microstrip) and inner (stripline) PCB layers. Crosstalk analysis is performed in 2D simulation and S-parameters are subsequently observed.

Introduction to Crosstalk

Crosstalk is an unintentional electromagnetic (EM) field coupling between transmission lines on a PCB. This phenomenon becomes a major culprit in signal integrity (SI), contributing to the rise of bit error occurrence in data communications and electromagnetic interference (EMI). With the existence of mutual inductance and capacitance between two adjacent transmission lines on a PCB, crosstalk has become more severe due to the shorter signal rise/fall times at today’s higher data speed rates.

Crosstalk can be minimized by routing the PCB traces further apart and reducing the dielectric thickness between PCB trace and reference plane. We will observe how a PCB’s dielectric thickness affects the signal crosstalk. All crosstalk analyses are carried out in 2D simulation using Mentor’s HyperLynx.

To read this entire article, which appeared in the August 2018 issue of Design007 Magazine, click here.

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