Calculation Notes

A broadside coupled stripline is constructed between two reference planes, as shown.

Factors that influence the impedance calculation include:-

• Trace thickness (t)
• Height to plane (h_p)
• Height between traces (h_t)
• Trace width (w)
• Substrate dielectric (ε_r)

Z_{o}\approx \frac{80}{\sqrt{\varepsilon_{r}}}\times\ln\left(\frac{1.9\times(2h_{p}+t)}{(0.8w+t)}\right)\times \left(1-\frac{h_{p}}{4\times \left( h_{t}+h_{p}+t \right)}\right)

• RF Design Guide Systems, Circuits and Equations (ISBN 0-89006-754-6)
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• IPC-2141 Controlled Impedance Circuit Boards and High Speed Logic Design

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