A millimeter antenna excited by a beam waveguide

An obvious method for obtaining antennas for use at millimeter wavelengths is to scale antennas which have already been developed for use at lower frequencies. However, as the frequency is increased, decreased dimensional tolerances and increased losses place a limit on ones ability to use conventional antenna types at the higher frequencies. In the propagation of energy at millimeter wavelengths problems of this kind have been circumvented by the development of unique transmission methods such as " ", " ", and " " guides, dielectric image lines, the use of higher order modes in circular waveguide, and the electromagnetic beam waveguide of Goubau, Schwering, and Christian[1,2]. The advent of these efficient transmission methods at millimeter wavelengths give rise to the interesting problem of coupling energy between these types of guiding systems and free space in an efficient manner. It is the purpose of this paper to report on an antenna consisting of two dielectric lenses which is excited directly from an electromagnetic beam waveguide.