Differential Microstrip Impedance Calculator

Calculate Differential Microstrip Impedance









Formula

To calculate the Differential Microstrip Impedance (\(Z_d\)):

\[ Z_d = \frac{174}{\sqrt{\epsilon_r + 1.41}} \ln \left( \frac{5.98h}{0.8w + t} \right) \left(1 - 0.48 \exp \left( -0.96 \frac{d}{h} \right) \right) \]

Where:

What is Differential Microstrip Impedance?

Differential microstrip impedance is the impedance of a differential pair of traces on a PCB. It is an important parameter in high-speed digital and RF circuit design.

Example Calculation 1

Let's assume the following values:

Using the formula:

\[ Z_d = \frac{174}{\sqrt{4.5 + 1.41}} \ln \left( \frac{5.98 \times 1.5}{0.8 \times 2 + 0.035} \right) \left(1 - 0.48 \exp \left( -0.96 \frac{0.5}{1.5} \right) \right) \]

The differential microstrip impedance can be calculated accordingly.

Example Calculation 2

Let's assume the following values:

Using the formula:

\[ Z_d = \frac{174}{\sqrt{3.5 + 1.41}} \ln \left( \frac{5.98 \times 1}{0.8 \times 3 + 0.05} \right) \left(1 - 0.48 \exp \left( -0.96 \frac{0.2}{1} \right) \right) \]

The differential microstrip impedance can be calculated accordingly.