Modeling the Frequency-Dependent Series Parasitics of Ground–Signal–Ground Pads Used to Probe On-Wafer Microstrip-Line-Fed Devices
A methodology is introduced for modeling resistive losses in planar transmission lines that support the transverse electromagnetic mode. The methodology aims to accurately and systematically account for these losses by modeling the skin, proximity, edge, and surface roughness effects in a combined way. The results show a correlation with three measurements within 5%, and offer insight into the different sources of resistive losses at high frequencies. Considering a printed coplanar line as an example, approximately 8% of the resistive loss come from surface roughness, and 30% from the edge effects at 60 GHz. However, for a line with a higher conductivity metallization, this increases to 38% and 30%, respectively, from surface roughness and edge effects at only 20 GHz.