US 4,504,836 AGranted

Antenna feeding with selectively controlled polarization

AssigneeSeavey Engineering Associates, Inc.

InventorJohn M. Seavey

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Abstract

A flat face annular grooved metal surface surrounds a circular waveguide opening coupled to a small dipole radiator which excites the circular waveguide in its fundamental propagating mode (TE.sub.11). The dipole is arranged to rotate about its axis by means of an extension of its inner conductor, which forms a simple probe in a section of rectangular waveguide situated behind the circular waveguide. A dielectric shaft is fastened to the inner conductor and is brought to the outside of the rectangular waveguide where it is connected to a small motor. The motor is arranged so that it may be actuated remotely by any of several circuits. The dipole may be before the corrugated plate with bent arms. A pair of dipoles may be arranged perpendicular to each other with two separate coaxial connector antenna feed outputs for direct attachment to coaxial-type low-noise amplifiers.

Claims12

Dependent claims

In an antenna feed having a corrugated surface concentric about the axis of an adjacent circular waveguide having an open end and a closed end formed with a central opening the improvement comprising,

polarized dipole antenna means polarized in a predetermined direction rotatably mounted about said axis and coupled to said circular waveguide and spaced from the circular waveguide closed end,
means for rotatably supporting said antenna means for rotation about said axis,
an output waveguide means for exchanging energy with said dipole antenna means through said central opening,
means for coupling said dipole antenna means to said output waveguide means through said central opening comprising an insulating mechanical bearing sleeve seated in said central opening and a coaxial transmission line seated in said sleeve connected to said dipole antenna means and including a coaxial impedance transformer for improving the impedance match between said dipole antenna means and said output waveguide means,
and means for rotating the assembly comprising said coaxial transmission line and said dipole antenna means to selectively control the polarization of said antenna feed about said axis,
wherein the axial length of said central opening is substantially a quarter wavelength, said dipole antenna means includes at least one pair of arms each substantially a quarter wavelength long extending radially outward from said axis, and the distance between said arms and said closed end is substantially a quarter wavelength.

3 more elements

Dependencies are inferred from the claim text.