On the electromagnetic field of a dielectric coated coaxial cable with an interrupted shield

A boundary value treatment is used to derive field expressions for a dielectric coated coaxial cable with a gap in the shield. Specific results are given for an incident TEM mode in the interior coaxial region. For example, it is shown that, for the VHF region, as much as 18 percent of the incident power is radiated into the external region via a single circumferential gap in the shield. Comparable amounts of power are transferred to a reflected TEM mode in the cable and into surface waves in the dielectric jacket.