Calculation method and supported range
Uses the same validated Hammerstad–Jensen model as the microstrip tool. Calculates all 16 endpoint combinations of w, h, t and Dk. Sensitivities vary one input between its endpoints while all others remain nominal.
Quasi-static, single trace above an infinite ground, air above, uniform isotropic nonmagnetic substrate. Supported tool range: 1 ≤ Dk ≤ 20, 0.05 ≤ w/h ≤ 20, t/h ≤ 0.2 and t/w ≤ 0.25. No solder mask, dispersion, loss, roughness or nearby copper is included. Validate the finished stackup with a field solver and measurement. Every corner must be valid. Reported limits are the evaluated corner envelope, not a statistical confidence interval or guaranteed manufacturing yield. Correlations and manufacturing distributions are not assumed.
Technical sources
Using the result
The tool evaluates the endpoints of an input tolerance box. This reveals useful sensitivity, but does not assign probability or manufacturing yield. Correlated process changes, etch shape, mask and copper roughness need additional modeling and measured process data.
From a calculation to a released design
Keep the input assumptions with the result. Recalculate when the ordered material, dielectric height, copper or operating conditions change. Confirm the final construction with the fabricator and use field simulation or measurement wherever the simplified model omits an important effect.
See the controlled-impedance guide and material selection workflow for the next checks.