This stripline impedance calculator finds the characteristic impedance of a trace buried between two ground planes, from the plate spacing, trace width, thickness, and dielectric. Enter the values above.
Formula
Z₀ = (60 ÷ √εr) × ln( 4b ÷ (0.67π(0.8W + t)) )
- b — ground-plane spacing, W — trace width, t — trace thickness
Example
εr = 4.4, b = 1.6 mm, W = 0.3 mm, t = 0.035 mm: Z₀ ≈ 68.7 Ω.
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Frequently Asked Questions
What is stripline?
A stripline is a PCB trace fully buried in dielectric between two ground planes, giving good shielding and a pure TEM mode.
How does stripline differ from microstrip?
Microstrip runs on the surface with air above; stripline is buried between grounds, so it has a higher effective dielectric and no radiation.
How do I hit a target stripline impedance?
Adjust the trace width and the ground-plane spacing; a wider trace or closer planes lowers the impedance.