Effect of connector contact points on common-mode current on a coaxial transmission line

In this paper, we present the results from two sets of independently performed experiments-real and simulated- which adopt the contact failure model. This model provides an explanation of contact failures caused by faulty transmission line connectors for the purpose of investigating the common-mode (CM) current, which is one of the factors that cause noise radiation. In the first experiment, CM current is measured while gradually increasing contact resistance. In the second experiment, the effect on CM current as the number of contact points is gradually decreased is examined. Both experiments are performed within the uplink bandwidth of cable television (CATV) internet transmission. From both sets of experimental results, we conclude that, in order to maintain electromagnetic compatibility of transmission lines in CATV, it is important for the contact boundary of a connector to have low contact resistance, a sufficient number of contact points, and a symmetric contact distribution.