SPICE model extraction for signal integrity analysis of unshielded twisted pairs from full wave simulation

Improved SPICE-like macromodels are proposed to model unshielded twisted pairs (UTPs). The equivalent SPICE circuits of UTPs cable are obtained by applying suitable extraction techniques based on the vector fitting procedure to the scattering matrix representation of the cable. The proposed SPICE models are suitable to analyze the transmission properties of UTPs taking into account frequency-dependent losses, proximity effect, and radiation losses. The characterization of the UTPs cable by the scattering matrix is here performed by a three dimensional full-wave numerical tool based on the finite integration technique. The proposed extraction procedures are absolutely general and can be also applied to measured scattering parameters. The UTPs SPICE models are validated by comparing the results with those provided by the full-wave simulation and by measurements