High-speed digital guru Bert Simonovich has published a white paper Practical Fiber Weave Effect Modeling. Bert uses ADS to help overcome this impairment.
Fiber-weave effect is becoming more of an issue as bit rates continue to soar upwards to 5 GB/s and beyond. Due to the non-homogenous nature of printed circuit board laminates, the fiberglass weave pattern causes signals to propagate at different speeds within differential pair traces, causing timing skew and mode conversion at the receiver, leading to reduced bit-error-rate (BER) performance, and increased EMI radiation. The relative dielectric constant (Dk) surrounding a trace ultimately determines its propagation delay. This paper delves into the issue and presents a novel approach to practically establish worst-case min/max values for Dk and use them to model this effect using ADS.
Click on the link Practical Fiber Weave Effect Modeling to download the PDF.
Thanks again, Bert!