RO4350B PCB Design Tools and Assumptions

The homepage microstrip estimator is a first-pass calculation for a uniform conductor above a continuous ground plane. Open the interactive estimator.

Inputs and units

Enter conductor width and dielectric height in millimeters, relative permittivity as a dimensionless value, and frequency in GHz. The estimated characteristic impedance is expressed in ohms. Quarter-wave length is expressed in millimeters.

Model limitations

The tool assumes zero copper thickness and a quasi-static field distribution. It does not include conductor roughness, solder mask, anisotropy, conductor trapezoid, neighboring traces, via transitions or connector launches. The supported width-to-height ratio is 0.1 through 10. Results outside that range are rejected rather than extrapolated.

Frequency interpretation

Frequency is used for the wavelength calculation. It does not change the quasi-static impedance calculation. Do not use the tool as a loss simulator or as proof of performance at a specified microwave frequency.

Next verification step

Transfer the intended structure into a suitable field solver, include the finished dimensions, and correlate the result with a representative test coupon. Record the solver settings and the measurement reference planes with the design revision.