Analysis of the Radiation from a Complex Multi-Conductor Transmission Line

Abstract

The Deployment of Power Line Transmission

(PLT) and the development of new broadband services over the

telephone network through technology like xDSL (x Digital

Subscriber Line), requires higher data rates, consequently

higher bandwidths, and operating frequencies. So it is generally

accompanied with electromagnetic compatibility (EMC)

phenomena, in particular the radiated emissions associated to

the deployed system and used cables characteristics. In fact the

electrical cable presents variations in their geometry, causing an

increase in the electromagnetic radiation. This paper presents a

theoretical approach to study a complex transmission line

network over ground plane. This approach leads to an analytical

expression for the evaluation of P.U.L. parameters of finite

length twisted wires lines. These expressions give the

capacitances and the inductances values in every point of the

cable, the theoretical results are compared to measurements.

The formalism is also derived to determine the distribution of

the electromagnetic field radiated by Shielded or Unshielded

Twisted Pair cables with discontinuity. The obtained results are

compared to those provided by a code based on the antenna

theory.