Patent ID: 8878740

Claim:
A horn antenna for a radar device comprising: a metal body containing a tubular hollow waveguide section opening into a hollow horn section and containing a circumferential recess at an outside of the metal body, a bottom of the circumferential recess providing a shoulder; a dielectric filling body filling up the inner space of the hollow horn section, the dielectric filling body comprising a cylindrical section slidably engaged within the tubular hollow waveguide section; a dielectric cover surrounding the metal body and covering the filling body at an aperture of the horn section to form a protective covering of the horn antenna, the dielectric cover further including a collar provided at an end portion of the dielectric filling body, the collar extending over an edge of the hollow horn aperture and further extending back toward the shoulder provided by the bottom of the circumferential recess; an inner surface of the hollow horn section and an outer surface of said dielectric filling body having a circumferential gap therebetween, the circumferential gap providing compensation for different thermal expansions of said dielectric filling body and said hollow horn section; and at least one spring supporting the end portion of the dielectric filling body against the shoulder, said spring pressing the dielectric filling body against the dielectric cover.