Stipline Impedance Calculator

How to Use This Calculator

1. Enter the strip width (w) in millimeters. This is the width of the conductive strip.
2. Enter the substrate height (h) in millimeters. This is the distance between the strip and the reference plane.
3. Enter the dielectric constant (ε_r) of the substrate material. Common values range from 2.2 to 4.5.
4. Enter the operating frequency in GHz. This affects the impedance at different frequencies.
5. Click the "Calculate" button to compute the characteristic impedance.

Working Principle

The characteristic impedance (Z₀) of a microstrip line (stipline) determines how electrical signals propagate along the line. It depends on the physical dimensions of the line and the dielectric properties of the substrate material.

The formula used in this calculator is an approximation for microstrip lines and works well for typical values. For more precise calculations, especially at higher frequencies or with special geometries, more complex formulas or electromagnetic simulation tools may be required.

Example

If you have a strip width of 1.0 mm, substrate height of 2.0 mm, and a dielectric constant of 3.5, the characteristic impedance at 1 GHz would be approximately 50.71 Ω.

Applications

This calculator is useful for RF and microwave engineers designing PCBs, coaxial-to-microstrip transitions, and other high-frequency transmission lines. Proper impedance matching is crucial for minimizing signal reflection and ensuring efficient power transfer.