Calculation Notes

An asymmetric stripline is constructed between two plane layers, where the distance above the trace is not equal to the distance below.

Factors that influence the impedance calculation include:-

• Trace thickness (t)
• Height above trace (h_a)
• Height below trace (h_b)
• Trace width (w)
• Substrate dielectric (ε_r)

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

• RF Design Guide Systems, Circuits and Equations (ISBN 0-89006-754-6)
• High-Speed Digital Design (ISBN 0-13-395724-1)
• Signal Integrity Issues and Printed Circuit Board Design (ISBN 0-13-335947-6)
• IPC-2141 Controlled Impedance Circuit Boards and High Speed Logic Design

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