Short horn radiator assembly

Claim 1

A short horn radiator assembly for operation over a predetermined band of operating frequencies, said assembly comprising: a short horn radiator for radiating electromagnetic radiation into an external propagation medium, said horn radiator having a radiation port, a waveguide port, a pair of oppositely disposed broad walls and a pair of oppositely disposed narrow walls oriented perpendicular to said broad walls, said walls extending longitudinally between said radiation port and said waveguide port, said horn having a length from said waveguide port to said radiation port of less than 1/2 wavelength at any one of said operating frequencies; a dielectrically loaded waveguide connected to said waveguide port of said horn, said dielectrically loaded waveguide comprising a rectangular waveguide and a body of dielectric material within said waveguide, said waveguide having a pair of oppositely disposed, parallel broad walls and a pair of oppositely disposed, parallel narrow walls oriented perpendicular to said broad walls, said body of dielectric material extending between said broad walls of said loaded waveguide, said waveguide oriented with its broad walls adjacent the broad walls of said horn, said broad walls of said horn being broader than said broad walls of said waveguide, said waveguide electrically coupled to said horn at said waveguide port and having each of its broad walls electrically shorted to the adjacent broad wall of said horn; and a portion of said body of dielectric material protruding beyond the end of said waveguide, through said waveguide port, into said horn and terminating within said horn, said protruding dielectric having a larger effective dielectric constant than the effective dielectric constant within the rest of the portion of said horn into which said dielectric protrudes.