Abstract: A dual band high efficiency hybrid offset reflector antenna system (10) that includes a low frequency antenna (12, 16) including a paraboloidal main offset reflector (12) for reflecting a low frequency signal, as well as a high frequency antenna (12, 14, 18) including both the main offset reflector (12) and a hyperboloidal subreflector (14) for reflecting a high frequency signal discrete from the low frequency signal. The hyperboloidal subreflector (14) includes a frequency selective surface (33) that passes the low frequency signal reflected by the paraboloidal main offset reflector (12) with low subreflector diffraction loss, and that is highly reflective at the high frequency. Offset beam squint pointing error can be eliminated because the high and low frequency bands have separate feed focal locations (30a, 30b).

Abstract: A dual band high efficiency hybrid offset reflector antenna system (10) that includes a low frequency antenna (12, 16) including a paraboloidal main offset reflector (12) for reflecting a low frequency signal, as well as a high frequency antenna (12, 14, 18) including both the main offset reflector (12) and a hyperboloidal subreflector (14) for reflecting a high frequency signal discrete from the low frequency signal. The hyperboloidal subreflector (14) includes a frequency selective surface (33) that passes the low frequency signal reflected by the paraboloidal main offset reflector (12) with low subreflector diffraction loss, and that is highly reflective at the high frequency. Offset beam squint pointing error can be eliminated because the high and low frequency bands have separate feed focal locations (30a, 30b).

Abstract: A satellite antenna system employing a dual-band feed horn and dual-band beam forming network. The feed horn provides a common aperture for both satellite uplink and downlink communications signal. The feed horn includes corrugations on an inside surface defining two sets of alternating channels having different depths to create circularly symmetric beams for the uplink and downlink signals. The antenna system includes at least one reflector, where the reflector shape, position, and the configuration of the feed horn, is determined so that the mainlobe of the lower frequency downlink feed signal illuminates the entire reflector, and the mainlobe of the higher frequency uplink feed signal illuminates an inner portion of the reflector. The first sidelobes of the higher frequency feed signal illuminate the outer portion of the reflector so that the uplink and downlink antenna signals have the same beamwidth, and thus cover the same cell size on the Earth.

Abstract: In accordance with the present invention, a traveling wave coupler generates tracking signals from a circularly polarized microwave signal and includes a waveguide manifold for exciting circular TM.sub.01 and TM.sub.11 modes of said circularly polarized microwave signal. The waveguide manifold includes an input port, a propagation length, and an output port. A coupling arm waveguide includes an auxiliary input port and an auxiliary output port and is aligned and connected to the waveguide manifold along a portion of the propagation length. A coupler located between the waveguide manifold and the coupling arm transforms microwave energy of a TM.sub.01 mode of the circularly polarized microwave signal into a rectangular TE.sub.10 mode in the coupling arm waveguide. The coupling arm waveguide and the coupler generate a difference signal, used to generate the tracking signals, at the auxiliary output port related to the coupled TE.sub.10 mode.