Modeling of Imperfectly Shielded Coaxial Cables by Surface Conductivity Boundary Condition

In this paper, we briefly discuss the validity of modeling imperfectly shielded transmission lines such as coaxial cables by a surface conductivity boundary condition. This approach is attractive for numerical simulations since it replaces the complex shielding structures by a homogenized surface boundary condition. We also present and validate a modified Coupled Transmission Lines model in order to introduce the surface conductivity representation, and show the equivalency with the surface transfer impedance. Numerical examples are provided to illustrate the effect of representing the cable’s shield by a surface conductivity boundary condition on crosstalk in practical EMC scenarios.