Multibeam antenna feed device
First Claim
1. A feed device for a multibeam antenna, said antenna providing Nb beams by means of Ne feed elements cooperating with a focusing means, each of the beams being generated by a sub-group of Nc feed elements, the feed elements being shared among overlapping beams, said feed device comprising:
- a set of Nc hybrid, multiport power dividers, each having an equal number of input ports and output ports, said number of input ports or output ports being a power of two, a power of three, or a product of a power of two and a power of three, the number of said output ports being Na, which number is equal to or greater than Ne, each of said feed elements of the antenna being excitable by one of said output ports so that for each beam provided by the antenna, each divider feeds one of the feed elements contributing to the respective beam, and each of said power dividers including an orthogonal and unitary distribution matrix;
a set of Na amplifier modules, each input port of said power dividers being connected to one of said modules, each said module comprising at least one of a transmission power amplifier and a low-noise reception amplifier, all of said amplifiers essentially operating at the same optimum nominal signal level responsive to changes in the relative loading of the beams; and
a beam forming network having Nb input ports and Na output ports, each input port of said network being connected to each output port of said network by means providing appropriate insertion phase shifts for each beam, each of said Na output ports being connected to one of said Na amplifier modules connected between said dividers and said beam forming network.
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Abstract
A multibeam antenna comprising Ne feed elements and emitting Nb beams each generated by a group of Nc elements has a feed device comprising a set of Nc power dividers. These power dividers are unitary orthogonal distribution matrix power dividers of order P, where P is equal to the power of two equal to or immediately higher than the ratio Ne/Nc. The outputs of the dividers are connected to the various elements in such a way that each element of one of the aforementioned groups contributing to a beam is connected to a different power divider and so that adjacent beams share feed elements. A beam forming network has P×Nc outputs connected to amplifiers in turn connected to the inputs of the power dividers. This network has Nb inputs. The beam forming network is usually a low-level network. The device finds a specific application in satellite communications.
168 Citations
18 Claims
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1. A feed device for a multibeam antenna, said antenna providing Nb beams by means of Ne feed elements cooperating with a focusing means, each of the beams being generated by a sub-group of Nc feed elements, the feed elements being shared among overlapping beams, said feed device comprising:
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a set of Nc hybrid, multiport power dividers, each having an equal number of input ports and output ports, said number of input ports or output ports being a power of two, a power of three, or a product of a power of two and a power of three, the number of said output ports being Na, which number is equal to or greater than Ne, each of said feed elements of the antenna being excitable by one of said output ports so that for each beam provided by the antenna, each divider feeds one of the feed elements contributing to the respective beam, and each of said power dividers including an orthogonal and unitary distribution matrix; a set of Na amplifier modules, each input port of said power dividers being connected to one of said modules, each said module comprising at least one of a transmission power amplifier and a low-noise reception amplifier, all of said amplifiers essentially operating at the same optimum nominal signal level responsive to changes in the relative loading of the beams; and a beam forming network having Nb input ports and Na output ports, each input port of said network being connected to each output port of said network by means providing appropriate insertion phase shifts for each beam, each of said Na output ports being connected to one of said Na amplifier modules connected between said dividers and said beam forming network. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10, 11, 12, 13, 14, 15, 16, 17, 18)
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Specification