Synthesis of a High Efficiency Conical-Horn Antenna: Effect of the Negative Flare Angle

In this paper, we propose a method to realize a high efficiency multiple-mode conical-horn antenna with low cross polarization. Contrary to usual horn antennas, a novel horn antenna proposed here is composed of a lot of small-taper sections not only with the positive flare angle, but also with the negative one. Introducing the negative flare angle make it possible to control simultaneously both the amplitude and the phase distributions on the horn aperture, so that the axial length of the horn can be made short enough.