In situ stripline laminate property extraction accounting for effective surface roughness losses

A method of extracting the effective copper surface roughness of a laminate in situ is introduced. The rough copper attenuation, as a function of surface roughness, is removed from the total attenuation. The residual loss is fit to coefficients, and an error is calculated based on the remaining surface roughness contribution. When the error is minimized or when the apparent surface roughness contribution is zero, the effective surface roughness and dielectric loss contribution are found. Using this extracted dielectric loss, broadband causal laminate electrical properties are calculated with higher accuracy than existing methods that neglect copper surface roughness. The new method uses S-parameter measurements of stripline traces and does not require a cross-section of the sample.