<math> Z_0 = \frac{120\pi}{\sqrt{\epsilon_{eff}}} \left[ \frac{w}{h} + 1.393 + 0.677 ln \left( \frac{w}{h} + 1.444 \right) \right] ^{-1} </math>
where w and h are the microstrip width and substrate thickness, respectively, and ε<sub>r</sub> is the relative permittivity of the dielectric. The above formulas are valid for the case of w/h ≥ 1. For your microstrip line defined in this project, you have w = 4.7mm, h = 1.5mm and ε<sub>r</sub> = 2.2. For these values, the above formulas give: Z<sub>0</sub> = 5949.554Ω and ε<sub>eff</sub> = 1.87, which are not far from the simulated results.
If you have installed [[RF.Spice A/D]] on your computer, you can also produce similar results in its Device Manager. In that case, you can access the [[RF.Spice A/D]] Device Manager directly from the '''Tool Menu''' of [[EM.Ferma]].