User:Tahsin Akalin

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Also "G-line." It is a single wire transmission line intended for use at UHF and microwave wavelengths [1]. The 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. G-lines behave more as waveguides than as circuitry. Bends of large radius are tolerated, but too sharp a bend in the single wire will cause the line to radiate and lose energy into space. In theory the dielectric coating is a requirement, it slows the wave and focuses it along the wire. But some users note that in practice the finite conductivity of metals may produce a similar effect, and a bare G-line can entrain a propagating wave. Note that the Goubau-Line are not exclusively obtained from 3 dimensionnal horn antennas and used in UHF or Microwave Frequencies. They can be "launched" from planar structures like tapered Coplanar Waveguides (CPW) at much higher frequencies such as the Terahertz Band [2]. The dimension of the single metallic conductor is then typically 1µm.

[1] Geog Goubau, "Surface waves and their Application to Transmission Lines," Journal of Applied Physics, Volume 21, Nov. (1950) [2] T. Akalin, A. Treizebré and B. Bocquet, “High Resolution Biosensor based on Surface Wave Transmission Lines at THz Frequencies”, 35th European Microwave Conf., 3-7 Oct. 2005, Paris, France