High performance multimode horn for communications and tracking

A multimode horn used to feed an antenna includes a generally tapered wall for transmitting and/or receiving an electromagnetic signal there through. The wall flares radially outwardly from a throat section to an aperture and defines an internal surface having a plurality of discontinuities. The geometry of the discontinuities are configured and sized to alter the dominant mode, which conveys the communications signal, into a higher order symmetrical mode content to achieve a balance between a plurality of communications performance parameters of the antenna over a pre-determined frequency range of the signal. The discontinuities are also designed to match the horn impedance for the modes of the communications signal and for an asymmetrical mode content of a simultaneously propagating tracking signal.