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US 4,903,037 AGranted
Dual frequency microwave feed assembly
AssigneeAntenna Downlink, Inc.
InventorsRodney A. Mitchell, Gerry B. Blachley
Life of this patent
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Abstract
A dual frequency feed assembly for antenna systems employing a pair of rotatably mounted probes each in respective coaxial cavities. The smaller cavity is supported by the rotating means for the larger probe and the smaller probe rotates with the larger probe driven by a common motor. The higher frequency signal is taken from the side wall of the lower frequency cavity. In an alternate embodiment, the smaller cavity is supported by a spider which rotates the smaller probe by means of external gearing and a separate motor. Other embodiments show coaxial lines which enter from the front face of the assembly and allow rotation of the smaller probe.
Claims21
A coaxial feed assembly for receiving electromagnetic signals and conveying them to a signal utilization means outside of said coaxial feed assembly comprising:
- a body defining a circular aperture and a first circular waveguide cavity therein having at least one sidewall and an end wall;
- a first probe mounted within said first circular waveguide cavity for receiving electromagnetic energy in a first preselected band of frequencies;
- means supporting said first probe in said first circular waveguide cavity;
- a first rectangular waveguide section mounted on said body;
- means conducting electromagnetic energy received by said first probe to said first rectangular waveguide section;
- whereby electromagnetic energy detected by said first probe may be conducted via said first rectangular waveguide section to a signal utilization means;
- means defining a second circular aperture and second circular waveguide cavity therein of smaller dimension than said first circular waveguide cavity;
- a second probe mounted within said second circular waveguide cavity for receiving electromagnetic energy in a second preselected band of frequencies, said second preselected band of frequencies being higher than said first band frequencies;
- dielectric means supporting said second probe in said second circular waveguide cavity;
- means mounting said second circular waveguide cavity coaxially within said first circular waveguide cavity and spaced from each of the walls of said first circular waveguide cavity;
- a second rectangular waveguide section mounted on said body;
- a coaxial line extending into said first circular waveguide cavity for conducting electromagnetic energy received by said second probe to said second rectangular waveguide section;
- wherein the means mounting said second circular waveguide cavity within said first circular waveguide cavity includes said coaxial line for conducting electromagnetic energy received by said second probe.
10 more elements
A coaxial dual frequency antenna feed assembly comprising a generally circular horn defining a first circular aperture and waveguide cavity having boundary walls;
- a first probe for detecting electromagnetic energy in a first frequency band exposed to incident electromagnetic energy in said first circular aperture and positioned within said first waveguide cavity including a portion thereof coaxial with said first circular aperture and waveguide cavity;
- means outside of said first circular aperture and waveguide cavity for rotating said first probe to change the polarization thereof;
- means defining a second circular aperture and waveguide cavity of smaller size than said first circular aperture and waveguide cavity;
- a second probe exposed to incident electromagnetic energy in said second circular aperture and positioned within said second waveguide cavity for detecting electromagnetic energy entering said second circular aperture in a higher frequency band than electromagnetic energy detected by said first probe;
- means for positioning said means defining said second circular aperture and waveguide cavity coaxially within said first circular aperture and waveguide cavity and wherein said means defining said second aperture and waveguide cavity is spaced from all of the boundary walls of said first circular aperture and waveguide cavity;
- signal conducting means for transmitting electromagnetic energy detected by said second probe to the exterior of said first circular waveguide cavity;
- and
- means for rotating said second probe to change the polarization thereof
- said means for rotating said second probe extending longitudinally through a portion of said first waveguide cavity and into probe rotational coupling engagement with said second cavity.
6 more elements
A coaxial dual frequency antenna feed assembly comprising a generally circular horn defining a first circular aperture and waveguide cavity having boundary walls;
- a first probe for detecting electromagnetic energy in a first frequency band exposed to incident electromagnetic energy in said first circular aperture and positioned within said first waveguide cavity including a portion thereof coaxial with said first circular aperture and waveguide cavity;
- means outside of said first circular aperture and waveguide cavity for rotating said first probe to change the polarization thereof;
- means defining a second circular aperture and waveguide cavity of smaller size than said first circular aperture and waveguide cavity;
- a second probe exposed to incident electromagnetic energy in said second circular aperture and positioned within said second waveguide cavity for detecting electromagnetic energy entering said second circular aperture in a higher frequency band than electromagnetic energy detected by said first probe;
- means for positioning said means defining said second circular aperture coaxially within said first circular aperture and waveguide cavity and wherein said means defining said second aperture is spaced from the boundary walls thereof;
- signal conducting means for transmitting electromagnetic energy detected by said second probe to the exterior of said first circular waveguide cavity;
- and
- means for rotating said second probe to change the polarization thereof;
- wherein said means for rotating said second probe includes means for supporting said means defining said second aperture and waveguide cavity;
- and
- wherein said means for supporting said means defining said second aperture comprises a harp extending around said first probe and engaging the said means for defining said second circular aperture.
8 more elements
Dependencies are inferred from the claim text.