Horn antenna with constant wave-beam

The utility model relates to a horn antenna with constant wave-beam, comprising a horn radiator, a horn activation section, wherein, the horn radiator is connected with the horn activation section; the horn radiator comprises a horn fan-shaped surface, and the horn fan-shaped surface introduces a cylindrical bore surface to the horn radiator, and the flare angle of the fan-shaped surface is about equal to two times of the wave-beam width, the radius of the fan-shaped surface is larger than the ratio of the half wavelength and the radius of the fan-shaped surface, and the E horn surface is provided with the flare angle of 1degree-2degrees; the horn activation section comprises a transition ridge, a coaxial-line outer conductor, a coaxial-line inner conductor, a rectangular waveguide, and a rear cavity, wherein, one end of the transition ridge is connected with the coaxial-line, which leads the main module impedance to be about 50omega, and the coaxial-line outer conductor is connected with the broadside of the