signal integrity

Microstrip Transmission Lines Impedance

Computes the characteristic impedance Z0 of a microstrip transmission line. Automatically selects the narrow trace formula (w/h < 1) or wide trace formula (w/h ≥ 1) based on the ratio of trace width to dielectric height.

Inputs

Dielectric Constant

Relative dielectric constant of the substrate — FR4: ~4.5, Rogers 4003: ~3.55

Dielectric Height

Height of the dielectric substrate (any consistent unit)

Width

Width of the trace (same unit as dielectric height)

Results

⚠Dielectric height must be greater than zero

Impedance Z₀—ΩCharacteristic impedance in ohms