A physical model for skin effect in rough surfaces

Insertion loss measured on PCB transmission lines operated in the two-digit Gigahertz range yields responses that exceed those simulated with geometry and material parameters. At such frequencies, the loss due to skin effect can no more be calculated assuming perfectly smooth conductor surfaces, as the skin depth would reach and fall below the dimension of surface roughness. Various phenomenological and topological models have been presented to account for this issue. Phenomenological models tend to need additional parameters to correct for new materials and frequency ranges, while topological models inherently use many parameters and often require significant computation effort. As an alternative, this paper suggests a comprehensive, single-parameter and fast computable physical model that accurately predicts measured responses.