Patent ID: 7642982

Claim:
An antenna feed horn extending in a signal propagation direction, comprising: a reception end defined by an undivided, oblong input aperture; a first output port spaced apart from the input aperture in the signal propagation direction, a first phase adjustment structure extending from the input aperture to the first output port, a second output port spaced apart from the first output port in the signal propagation direction, and a second phase adjustment structure extending from the first output port to the second output port; a diplexer for directing a first signal propagating at a first desired frequency exhibiting circular polarity expressed by orthogonal linear components when incident at the input aperture the first output port, and for directing a second signal propagating at a second desired frequency exhibiting circular polarity expressed by orthogonal linear components when incident at the input aperture to a second output port; for the first signal, the interior surface of the first phase adjustment structure configured to differentially phase shift the linear components by approximately 90 degrees to convert the signal from circular polarity to linearly polarity as the first signal propagates through the first phase adjustment structure from the input aperture to the first output port; and for the second signal, the interior surfaces of the first and second phase adjustment structures configured to differentially phase shift the linear components by approximately 90 degrees to convert the second signal from circular polarity to linearly polarity as the second signal propagates through the first and second phase adjustment structures from the input aperture to the second output port.