An antenna includes a reflector and a waveguide assembly. The waveguide assembly includes a feed assembly and a support member that extends from behind the reflector to orient the feed assembly for direct illumination of the reflector. The waveguide assembly includes a first waveguide coupled to a first portion of a common waveguide, a second waveguide coupled to a second portion of the common waveguide, and a septum layer that includes a septum polarizer coupled between the common waveguide and the first and second waveguides.