Unified multiconductor transmission-line model of multiple-shield multiconductor cables: evaluation of shield connections performances

This paper presents a unified transmission-line model of a multiple-shield multiconductor cable. This model includes, at the same time, the propagation and the cross-coupling characteristics of the electrical wires and the cable shields. It also includes the electromagnetic characteristics of the shields (in terms of transfer impedance and transfer admittance). It is derived in compliance with the multiconductor-transmission-line theory and can be applied whatever the connection configurations at both shield extremities. Therefore, it makes it possible the modelling of realistic cable shield connection problems ranging from ideal 360 degrees shield connections to simple bonding wires. The paper proposes a physical explanation of the derived per-unit-length matrices. This unified model is also used to define the required conditions for calculating the electromagnetic coupling response of a shielded cable in a two-step approach in which the shield problem and the inner shield problem are solved in sequence. Finally, the paper illustrates an application of the model in order to evaluate the performances of a shielded cable link on electromagnetic crosstalk configurations with respect to several electrical bonding solutions of the shield.