Horn antennas with integrated feeds

A method, comprising:

• forming a horn aperture having a footprint projected along a longitudinal axis, and integrated with a multimode feed network disposed within an envelope of the footprint;
• wherein the multimode feed network comprises:
• a first feed section having a folded serpentine arrangement and coupled between a first feed port and a first polarizer port of a polarizer, the first feed section comprising a first waveguide filter perpendicular to the polarizer and first waveguide stubs parallel to the polarizer establishing first transmission zeros;
• a second feed section having a folded serpentine arrangement and coupled between a second feed port and a second polarizer port of the polarizer, the second feed section comprising a second waveguide filter perpendicular to the polarizer and second waveguide stubs parallel to the polarizer establishing second transmission zeros;
• and
• the polarizer comprising a stepped septum positioned between the first polarizer port and the second polarizer port and having a shared port coupled to the horn aperture.

A radio frequency aperture assembly, comprising:

• a horn aperture having a footprint projected along a longitudinal axis;
• and
• a feed network disposed within an envelope of the footprint, the feed network comprising:
• a transmit feed section having a folded serpentine arrangement and coupled between a transmit feed port and a transmit polarizer port of a polarizer, the transmit feed section comprising a transmit waveguide filter perpendicular to the polarizer and transmit waveguide stubs parallel to the polarizer establishing first transmission zeros;
• a receive feed section having a folded serpentine arrangement and coupled between a receive feed port and a receive polarizer port of the polarizer, the receive feed section comprising a receive waveguide filter perpendicular to the polarizer and receive waveguide stubs parallel to the polarizer establishing second transmission zeros;
• and
• the polarizer comprising a stepped septum positioned between the transmit polarizer port and the receive polarizer port and having a shared port coupled to the horn aperture.