Embedded Microstrip Trace Impedance Calculator

  1. Fill in the relative permittivity and height of the dielectric and the height, width, and thickness of the trace.
  2. Select the Zo button to calculate the characteristic impedance of the trace.

You can also choose to fill in the desired characteristic impedance and leave one of the trace parameters blank. Selecting the button next to the blank field will calculate the missing parameter. Equations used to make these calculations are provided at the bottom of this page.

Units for T, the trace thickness:
mils Oz

er
H mils
H1 mils
mils
ohms
Calculation Results:
Zc ohms
Lo nH/in
Co pF/in
Tpd ns/in

ns/ft

Relative Permittivity Equation: IPC-D-317A (Eq. 5.35)

The formula in the IPC document for Zo is not consistent with the formula for the non-embedded microstrip, so it is not used here. The formula shown was retains the square root of epsilon dependence with a constant out front that is consistent with IPC-D-317A Eq. 5.32 for small values of epsilon and/or large values of H1.

If H1<1.2H, the formula for the non-embedded microstrip should be used.

embedded microstrip

Are there any distributed capacitive loads on this trace?
No Yes

If there are distributed loads, please provide the average length of the traces attachingthe loads and the average load capacitance.
Trace Length inches
Total Load pF


formula for embedded microstrip structure