Coaxial Plug Connectors in High-Frequency Applications

Coaxial lines lend themselves well to the wire-bound transmission of high-frequency signals. The have no lower frequency limit and thus are able to carry DC, as well. Moreover, the propagation velocity is constant across the whole usable frequency range as long as the cable is kept in the transversal electro-magnetic (TEM) mode. A disadvantage is the additional attenuation in the dielectric between outer and inner conductors. Compared to a WR-90 waveguide with 10.8 dB/100m at 10 GHz, a 1/2” Flexwell  cable  can merely offer 40.6 dB/100m. On the other hand, the wave-guide is solid pipe and it is not easily bent which is no issue at all for a coax cable. Even semi-rigid wires can be bent by hand using a tool which avoids deformation of the cross-section.To connect coax lines to devices or to other cables, various plug types were developed over time. Some of these have established themselves as a quasi-standard while others are not used anymore although they would have advantages over the existing systems.