This calculator determines the differential impedance (Zd) of an edge-coupled microstrip based on single-ended impedance, trace separation, and dielectric thickness. It helps PCB designers and RF engineers maintain signal integrity in high-speed differential pair designs.
Formula
Zd = 2 * Z0 * ( 1 – 0.48 * exp( -0.96 * (d / h) ) )
Formula Explanation
- Z0: Single-ended impedance (Ohms)
- d: Trace separation (mils)
- h: Dielectric thickness (mils)
- exp: Exponential function that models coupling effects between traces
Example
Input: Z0 = 50 Ω, d = 6 mils, h = 4 mils
Result: Zd ≈ 86.4 Ω
Who uses it
Ideal for PCB and RF engineers designing high-speed or differential signal traces where impedance control is critical.