Abstract: A splashplate antenna system configured using hybrid mode-matching techniques has improved secondary beam characteristics, including improved sidelobe performance, improved electric and magnetic plane correlation, reduced cross-polarization, improved electric and magnetic plane phase center correlation, and improved overall matching between the waveguide and the splashplate (sub-reflector). Internally, the waveguide contains a wall constructed from a series of varying dimensioned cross-sections that cause signals introduced to radiate in a multiple mode, Gaussian-like field pattern. The Splashplate is configured so that the waves received from the waveguide maintain the circular pattern symmetry, as well as other characteristics.

Abstract: A feed system for an antenna has a set of inner and outer coaxial waveguides which apply, respectively, both higher and lower frequency radiations to a common radiating aperture provided by a horn and shroud which envelops radiating apertures of the individual feed waveguides. Each of the feed waveguides carries signals having a bandwidth of an octave. Lower frequency radiation to be transmitted by the outer coaxial feed waveguide is applied thereto by a set of four waveguides of a launcher which launches a wave with a desired propagation mode into the outer feed waveguide. Each of the launch waveguides is initially a rectangular double-ridged waveguide for increase bandwidth. The ridging is reduced to a condition of no ridging in the outer feed waveguide by a transition to a single inner ridge which terminates in a tapered star-shaped combination ridge within the outer feed waveguide.