Launcher for plural band feed system
First Claim
1. A feed system for an antenna, the feed system comprising:
- an inner electrically conducting tube and an outer electrically conducting tube, a space within the inner tube constituting an inner feed waveguide, and a space between the inner tube and the outer tube constituting an outer feed waveguide;
means for applying a higher frequency radiation to the inner feed waveguide, and a launcher for launching a wave of lower frequency radiation in the outer feed waveguide;
wherein said feed waveguides have coaxial radiating apertures for radiation of signals at the higher and the lower frequencies from a common phase center; and
said launcher comprises a set of ridged launch waveguides merging with said outer feed waveguide, there being a tapering of ridges of said launch waveguides from a maximum value distant from said outer feed waveguide to a minimum value within a portion of said outer feed waveguide adjacent said launcher.
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Accused Products
Abstract
A feed system for an antenna has a set of inner and outer coaxial waveguides which apply, respectively, both higher and lower frequency radiations to a common radiating aperture provided by a horn and shroud which envelops radiating apertures of the individual feed waveguides. Each of the feed waveguides carries signals having a bandwidth of an octave. Lower frequency radiation to be transmitted by the outer coaxial feed waveguide is applied thereto by a set of four waveguides of a launcher which launches a wave with a desired propagation mode into the outer feed waveguide. Each of the launch waveguides is initially a rectangular double-ridged waveguide for increase bandwidth. The ridging is reduced to a condition of no ridging in the outer feed waveguide by a transition to a single inner ridge which terminates in a tapered star-shaped combination ridge within the outer feed waveguide. Impedance matching rings are slidable within the space between the inner and outer surfaces of the coaxial waveguide for development of a desired standing wave ratio for accurate generation of a desired beam pattern. A dielectric rod is disposed in a forward end of the tube of the inner feed waveguide and protrudes therefrom into the horn for shaping a beam of the higher frequency radiation. A single common phase center is provided for all bands with radiation simultaneously at plural bands.
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Citations
11 Claims
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1. A feed system for an antenna, the feed system comprising:
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an inner electrically conducting tube and an outer electrically conducting tube, a space within the inner tube constituting an inner feed waveguide, and a space between the inner tube and the outer tube constituting an outer feed waveguide; means for applying a higher frequency radiation to the inner feed waveguide, and a launcher for launching a wave of lower frequency radiation in the outer feed waveguide; wherein said feed waveguides have coaxial radiating apertures for radiation of signals at the higher and the lower frequencies from a common phase center; and said launcher comprises a set of ridged launch waveguides merging with said outer feed waveguide, there being a tapering of ridges of said launch waveguides from a maximum value distant from said outer feed waveguide to a minimum value within a portion of said outer feed waveguide adjacent said launcher. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11)
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Specification