Impact of Surface Roughness on Return Planes in High Speed Signal Propagation

Nowadays the impact of conductor surface roughness is extremely important as data rates continue to increase. There are several methods to model surface roughness on copper, e.g. Hemispherical model, Huray model, etc. However, very few studies show the effect of return/reference plane surface roughness on signal propagation. In this paper, the impact of surface roughness on both signal layer and reference plane is investigated.