A reflector antenna includes a dual-band waveguide feed and a splashplate support arranged to define a space between the waveguide feed aperture and the splashplate. The dual-band waveguide feed is configured to receive an input signal in a first transmission mode, the input signal including a plurality of frequencies arranged into upper and lower frequency bands, and includes means for converting a transmission mode of the upper frequency band from a first transmission mode to a mixed transmission mode including the first transmission mode and a second transmission mode. The supporting portion can be spaced apart from the aperture of the waveguide feed, and may have a thickness corresponding to half a wavelength of a beam emitted from the aperture. The shape of the supporting portion may preferably correspond to a shape of the beam wavefront after it has been reflected from the splashplate. A satellite including the reflector antenna is also disclosed.