Limited scan phased array system
AssigneeHughes Aircraft Company
InventorEdward C. DuFort
Life of this patent
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Abstract
A phased array antenna system is disclosed for scanning a narrow beam over a limited angular sector with near optimum performance while using the minimum number of active elements. An input corporate feed is coupled to a "thinned" array of phase shifters. Each phase shifter is coupled to one of a plurality of lossless periodic matrix sub-array feed networks. Radiating elements are coupled in periods such as three elements per period. The output of each phase shifter is selectively coupled to the array of radiating elements within its period and to elements in adjacent periods as well. Such an array permits a plurality of overlapping main beams having low side lobes and grating lobes.
Claims4
A limited scan phased array system for scanning a narrow beam over a limited angular sector, comprising:
- a predetermined number T antenna elements and a distribution network having a common input terminal and a predetermined number P distribution ports, where T and P are integers and M equals T/P which is equal to or greater than 3;
- P phase shifters each connected at its input discretely from a corresponding one of said distribution ports;
- and
- a lossless and passive sub-array interconnecting network having T output ports and P input ports, each of said output ports being connected discretely to a corresponding one of said antenna elements, and each of said input ports being connected discretely to the output of a corresponding one of said phase shifters, said lossless sub-array interconnecting network also including M first hybrid networks and M second hybrid networks, each of said first hybrid networks being a 1:M power divider having M output terminals and an input terminal connected discretely to one of said phase shifters, said predetermined number T antenna elements being equal to M times P.
Dependencies are inferred from the claim text.