Abstract: A multiple-beam antenna system includes at least one reflector and a cluster of horns for feeding the reflector. A horn of the cluster of horns is configured for providing transmission and reception of signals over respective transmission and reception frequency bands. The horn includes a substantially conical wall having an internal surface with a variable slope. The internal surface of the substantially conical wall includes slope discontinuities. At least one of the slope discontinuities has a diameter greater than 1.7 times the wavelength of the lowest frequency of the transmission frequency band. The diameter is also greater than 1.7 times the wavelength of the highest frequency of the transmission frequency band. In addition, the diameter is greater than 1.7 times the wavelength of the lowest frequency of the reception frequency band, and the diameter is greater than 1.7 times the wavelength of the highest frequency of the reception frequency band.