Efficient and accurate simulation of shielding effectiveness in coaxial cables

The subject of this paper is EM simulations of EMI field penetration into the coaxial cables. We investigate the three important mechanisms and the three levels of penetration: open ends, propagation through the solid outer shell wall with finite conductivity, and imperfections in the outer shell of the cable (small gaps in the braided wires). The induced power is compared in the three cases. When the shielding effectiveness is increased, the EM simulation gets more challenging, especially if high accuracy is required. Particularly, the model with braided shield is difficult to simulate for the extended cable length. An equivalency between the model with solid walls (and finite conductivity) and the model with strips replacing braided wires is established. The solid walls model is very efficient for simulation of very long cables (2 m cable at 10 GHz). The cable used as example is commonly used RG-58.