Formation of a given distribution of the radiation field from the end of a circular open dielectric waveguide

Sections of circular open dielectric waveguides are used as irradiators of radio interferometers of fast processes operating in the millimeter wavelength range. For correct diagnostics of the obtained results, it is necessary to have a radiation field from the end of the waveguide (wave beam) with a given distribution over transverse coordinates. The possibility of forming an axial radiation field from the end of a circular open dielectric waveguide with a given radial distribution has been theoretically shown, implying the use of a spatial filter in the form of a thin dielectric plate made of a material with an absorption coefficient changing according to a radial law, placed on the end of a conically expanding waveguide. The results of the work can be used in the construction of irradiators of UHF radio interferometers.