Electromagnetic analysis of metal braids

The shielding effectiveness of metal braids of cables is governed by the geometry and the materials of the braid. The shielding effectiveness can be characterised by the transfer impedance of the metal braid. Analytical models for the transfer impedance contain in general two components, one representing diffusion of electromagnetic energy through the metal braid, and a second part representing leakage of magnetic fields through the braid. The second part is a local phenomenon, which again has two parts: hole inductance and braid inductance. The paper will improved the analytical modelling of leakage of magnetic fields through the braid. Results of simulations are compared with measurements of several metal braids having different geometries.