Selected Measurements of Connectors, Backshells, and Cable Terminations

The surface transfer impedance of a variety of connectors, backshells, and cable terminations have been measured. Most of the RFI/EMI backshell terminations had a transfer resistance of about 0.1 milliohms and a transfer mutual inductance equivalent to less than a few cm (about an inch) of single braid. The MIL-C-38999, Series IV connectors (with backshells and double overbraid attached) were measured using an innovative inside-out triaxial fixture which could be used while the connectors were installed on a cable assembly. The mean transfer resistance was about 0.7 milliohms. The high frequency transfer impedance increased at the rate of 10 to 14 dB/decade suggesting that the electromagnetic performance was being limited by contact impedance rather than apertures.