Horn radiator assembly with stepped septum polarizer.

摘要

An array antenna is formed of a plurality of horn radiator assemblies (30) coupled to a beamformer. Each of the horn radiator assemblies has a first waveguide section (34) formed with square cross-section. A septum (38) begins at a middle portion of the waveguide section and increases stepwise to a maximum height at a back end of the waveguide section. A set of capacitive teeth are arranged in a row in front of the septum. The back end of the waveguide section is bisected by the septum into first and second rectangular waveguide ports. Each horn radiator assembly also includes a circular cylindrical horn (32) joined to the first waveguide section by an impedance matching section (36), the impedance matching section having second (48) and third (50) waveguide sections. The second waveguide section has circular cross section of smaller diameter than the horn and connects with the horn. The third waveguide section has square cross-section and a sidewall height which is less than the diameter of the second waveguide section. The third waveguide section connects with the front end of the first waveguide section. A circularly polarized wave entering the horn is converted to a linearly polarized wave which appears in one of the ports depending on the sense of the polarization. The stepped configuration of the impedance matching section minimizes mutual coupling among horns of the respective assemblies of the array antenna.