Guided-wave Propagation on a Cylindrical Conductor at Millimeter-wave or Terahertz Frequencies

摘要

Conventional wave guiding methods develop high loss and other disadvantages above 100 GHz. Alternatively, surface-wave propagation on coated or uncoated conducting wires, rods, or tubes has been shown to provide low attenuation, moderate field extent, low dispersion, and high power-handling at frequencies from 100 GHz to 1 THz. Typical conductors are copper, aluminum, or stainless steel. Uncoated conductors provide the lowest loss, while conductors coated with a thin layer of low-loss dielectric have the smallest field extent. The guided mode is the TM_(01), often referred to as the Sommerfeld mode. The properties of the guided wave were theoretically analyzed earlier by King and Wiltse, and measured results were obtained at 105 and 140 GHz. In the last two years the work has been rediscovered, and now four different research groups have reported new results. While the earlier work was conducted in the search for long, low-loss transmission lines, the current applications are for lengths about 1 meter long or less. The recent results will be summarized, and a preferred design will be suggested, along with general curves of attenuation, field extent, and power handling capability from 100 GHz to 1 THz.