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.

Dielectric constant

Required number input.

Substrate height (mm)

Required number input.

Trace width (mm)

Required number input.

Trace thickness (mm)

Required number input.

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

Microstrip impedance (Ω)

The resulting microstrip impedance returned as a number.

• Compact electronics formulas omit some combination of tolerances, temperature drift, bandwidth, loading, parasitics, noise spectrum, nonlinearity, clipping, calibration, layout, and device-specific limits. Typical datasheet values are not guaranteed limits.
• 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.

• CPW Impedance Approx

  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.

• 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))).

• Differential Z Approx

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