Calculation Notes

Broadside coupled traces are commonly found in printed circuit boards where differential pairs are routed. They are found on adjacent layers with the return being identical in length and width. This techique enables strong coupling, although the return is commonly on a plane layer.

Factors that influence the inductance calculation include:-

• Trace width (w)
• Trace separation (s)
• Trace length (l)
• Trace thickness (t)
• Relative permeability (µ_r)

\mu_{0} = 4\pi \times 10^{-7}\;Wb\;A^{-1}\;m^{-1} (permeability of free space)

Inductance \approx l\times \frac{\mu_{0}\times \mu_{r}\times s}{w}

where

w \gg s, s > t

References:

• Electrical Circuit Theory and Technology (ISBN 978-1-85617-770-2)
• Signal Integrity Issues and Printed Circuit Board Design (ISBN 0-13-335947-6)

Disclaimer: The information and this tool are provided with no liability of any kind whatsoever, use at your own risk.