Goubau line

A Goubau line or Sommerfeld-Goubau line, or G-line for short, is a single wire transmission line used to conduct radio waves at UHF and microwave frequencies. The dielectric coated transmission line was invented by F. Harms in 1907 and George J. E. Goubau in 1950, based on work on surface waves on wires from 1899 by Arnold Sommerfeld. It is used as a feedline at UHF to link high frequency transmitters and receivers to their antennas, and in scientific research.

Description

The Goubau line itself consists of a single conductor coated with dielectric material. Coupling to and from the G-line is done with conical metal "launchers" or "catchers, with their narrow ends connected for example to the shield of coaxial feed line, and with the transmission line passing through a hole in the conical tips." An advantage of the Goubou line is that it can have lower attenuation due to dielectric losses at high frequencies than other types of transmission line. Parallel line (twin lead) and coaxial cable, which are used to carry lower frequency radio signals, have high losses at the upper end of the UHF band, and are almost useless for distances over 100 feet (33 meters). Goubau lines can serve as low loss antenna feedlines at these frequencies, up to microwave frequencies where waveguide must be used."