Use this electronics calculation for a first-pass component, converter, signal, motor, or sensor estimate when the stated operating conditions and units match the device data.

Effective permittivity

Optional number input.

Trace-to-ground gap (mm)

Required number input.

Trace width (mm)

Required number input.

Approximate coplanar waveguide impedance as (60 / sqrt(er_eff)) x ln(4 x a / b) with a = w/2 + gap and b = w/2; er_eff defaults to 4. The tool evaluates the supplied inputs together and returns the named outputs below; it does not infer omitted operating conditions or change the units shown.^[1]

CPW impedance (Ω)

The resulting cpw impedance returned as a number.

• Closed-form transmission-line estimates assume a particular geometry, homogeneous or effective dielectric, conductor model, and frequency range. Fabrication tolerances, copper roughness, dispersion, solder mask, connectors, vias, and return-path discontinuities require field solving or measurement for precision work.
• Use finite inputs in the displayed units and preserve more precision than the final presentation requires. Independently verify safety-critical, financial, compliance, or production decisions.

Check the result against the current datasheet and worst-case operating corners, then verify the circuit or measurement with simulation and bench testing where failure matters.

• Stripline Z Approx

  Approximate symmetric stripline impedance as (60 / sqrt(er)) x ln(4 x h / (0.67 x pi x (0.8 x w + t))).

• Microstrip Z Approx

  Approximate microstrip characteristic impedance as (87 / sqrt(er + 1.41)) x ln(5.98 x h / (0.8 x w + t)).

• Differential Z Approx

  Approximate edge-coupled differential impedance as 2 x z0 x (1 - 0.48 x exp(-0.96 x s / h)).