Electronically scanned antenna

Claim 2

An electronically scanned antenna comprising N independent radiation aperture units adapted to form N raaiation beams in a first radiation plane, where N > 1, and a plurality of beam control means having a power variable distribution performance and a phase control performance, said control means performing radiation beam controls including switching of the radiation beams and setting of radiation power ratio for the respective raaiation beams to any desired values in said first radiation plane regarding said N radiation beams and raaiation beam scanning in a second radiation plane orthogonal to said first radiation plane in a predetermined reference direction with reference to said first radiation plane in which said N radiation beams are formed.

Claim 3

An electronically scanned antenna comprising N(N> 1) independent radiation aperture units for forming N radiation beams in a first radiation plane, wherein radiation elements of the radiation aperture units corresponding to respective one of said N radiation beams are arrayed alternately so as to commonly use substantially the same radiation aperture plane, and a plurality of beam control means having a power variable distribution performance and a phase control performance, said control means performing radiation beam controls including switching of the radiation beams, setting of radiation power ratio for the respetive radiation beams to any desired values and radiation beam scanning in the case of forming the radiation beams in the overlapping manner in said first radiation plane regarding said N radiation beams and radiation beam scanning in a second radiation plane orthogonal to said first radiation plane in which said N radiation beams are formed in a predetermined reference direction.

Claim 4

An electronically scanned antenna comprising N(N> 1) independent radiation aperture units for forming N radiation beams in a first radiation plane, wherein radiation elements of the radiation aperture units corresponding to respective one of said N radiation beams are arrayed alternately so as to commonly use substantially the same radiation aperture plane, and a plurality of beam control means having a power variable distribution performance and a phase control performance, said control means performing radiation beam controls including switching of the radiation beams, setting of radiation power ratio for the respetive radiation beams to any desired values and radiation beam scanning in the case of forming the radiation beams in the overlapping manner in said first radiation plane regarding said N radiation beams and radiation beam scanning in a second radiation plane orthogonal to said first radiation plane in which said N radiation beams are formed in a predetermined reference direction.

Claim 5

The electronically scanned antenna according to claim 1 or 2 wherein said radiation aperture units are rotated in a horizontal plane.

Claim 6

The electronically scanned antenna according to claim 1, 2 or 3 wherein said first and second radiation planes correspond to a horizontal radiation plane and a vertical radiation plane respectively, each of said N independent radiation aperture units forming said N beams is so constructed as to have M (M >1) input terminals formed by a vertical array of radiation elements, N input terminals at the same position of M sets of N independent radiation units are connected to respective N-output terminals of M beam control means, input terminals of said M beam control means are connected to a vertical feed .circuit having M output terminals, and power is supplied to said M beam control means through said vertical feed circuit.

Claim 7

The electronically scanned antenna according to claim 1, 2 or 3 wherein said first and second radiation planes correspond to a vertical radiation plane and a horizontal radiation plane respectively, each of said N independent radiation aperture units forming said N beams is so constructed as to have M (M >1) input terminals formed by a horizontal array of radiation elements, N input terminals at the same position of M sets of N independent radiation units are connected to respective N-output terminals of said M beam control means, input terminals of said M beam control means are connected to a horizontal feed circuit having M output terminals, and power is supplied to said M beam control means through said horizontal feed circuit.

Claim 8

The electronically scanned antenna according to claim 1, 2, 3, 4 or 5 wherein each of said beam control means comprises a power distributor equally distributing an input signal, a pair of electronically variable phase shifters connected to respective output terminals of said power distributor and controlled by an external signal, and a 90° hybrid coupler inputted with a pair of output signals of said electronically variable phase shifters, and wherein (N-l) two-output variable power phase shifters each having a pair of output terminals are connected in series and parallel corresponding to said N radiation beams thereby forming N output terminals corresponding to one input terminal.

Claim 9

An electronically scanned antenna comprising a radiation aperture unit forming N (N > 1) multi-radiation beams in a first radiation plane, and beam control means having a variable power distribution performance and a phase control performance, said beam control means performing rradiation beam controls including switching of the radiation beams, setting of radiation power ratio for respective radiation beams to any desired values and radiation beam scanning in the case of forming the radiation beams in the overlapping manner in said first radiation plane in which said multi-radiation beams are formed and radiation beam scanning in a second radiation plane orthogonal to said first radiation plane in which said multi-radiation beams are formed in a predetermined reference direction.

Claim 10

An electronically scanned antenna comprising a radiation aperture unit forming N (N > 1) multi-radiation beams in a first radiation plane, and beam control means having a variable power distribution performance and a phase control performance, said beam control means performing rradiation beam controls including switching of the radiation beams, setting of radiation power ratio for respective radiation beams to any desired values and radiation beam scanning in the case of forming the radiation beams in the overlapping manner in said first radiation plane in which said multi-radiation beams are formed and radiation beam scanning in a second radiation plane orthogonal to said first radiation plane in which said multi-radiation beams are formed in a predetermined reference direction.

Claim 11

The electronically scanned antenna according to claim 7 wherein said radiation aperture unit is rotated in a horizontal plane.

Claim 12

The electronically scanned antenna according to claim 7 or 8 wherein said first and second radiation planes correspond to a horizontal radiation plane and a vertical radiation plane respectively, said radiation aperture unit forming said N multi-radiation beam is formed by arraying in the vertical direction M (M>l) horizontal array units, each including a plurality of horizontally arrayed radiation elements, respective input terminals of said M horizontal array units are connected to the output terminals of said M control means, and a vertical feed circuit having M output terminals is connected to respective input terminals of said M beam control means for feeding power thereto.

Claim 13

The electronically scanned antenna according to claim 7 or 8 wherein said first and second radiation planes correspond to a vertical radiation plane and a horizontal radiation plane respectively, said radiation aperture unit forming said N multi-radiation beam is formed by arraying in the horizontal direction M (M > 1) vertical array units each including a plurality of radiation elements arrayed in the vertical direction, respective input terminals of said M vertical array units are respectively connected to output terminals of said M beam control means, and a horizontal feed circuit having M output terminals is connected to respective input terminals of said M beam control means for feeding powder to thereto.

Claim 14

The electronically scanned antenna according to claim 7, 8, 9 or 10 wherein each of said beam control means comprises a power distributor evenly distributing an input signal, a pair of electronically variable phase shifters conneted to output terminals of said power aistributor and controlled by an external signal, a 90° hybrid coupling circuit inputted with a pair of output signals from said electronically variable phase shifters for producing a pair of output signals, and wherein ( N -l) two-output variable power phase shifters are connected in series and parallel corresponding to said N multi-beams so as to form N output terminals corresponding to one input terminal.

Claim 15

The electronically scanned antenna according to claim 7 or 8 wherein said beam control means comprises: a variable power aistributor having one input terminal and N output terminals corresponding to said N multi-radiation beams, the output power of said variable power distributor being switchable or settable to any power ratios; N feed circuits connected to the respective output terminals of said variable power distributor, for distributing and feeding power to provide a predetermined power distribution to the antenna aperture units; and a phase shifter connected at one end to each output terminal of each feed circuit and at the other end to each input terminal of an input terminal group of said antenna aperture unit corresponding to each of the N multi-radiation beams, said phase shifter being controlled by an external signal.

Claim 16

An electromagnetic wave apparatus comprising an antenna which is mechanically rotatable in a horizontal plane and has a radiation unit for simultaneous formation of a plurality of beams in azimuth directions and a receiver for reception of the beams, wherein the plurality of beams are formed in such a way that the simultaneous beams are unsymmetrical in relation to the radiation center and the interval therebetween are unequal, and target data received at unequal time intervals corresponding to said plurality of beams are processed in terms of azimuth angle correlation to determine the azimuth of said target.

Claim 17

An electromagnetic wave apparatus comprising an antenna which is mechanically rotatable in a horizontal plane and has a radiation unit for simultaneous formation of a plurality of beams in azimuth directions and a receiver for reception of the beams, wherein the plurality of beams are formed in such a way that the simultaneous beams are unsymmetrical in relation to the radiation center and the interval therebetween are unequal, and target data received at unequal time intervals corresponding to said plurality of beams are processed in terms of azimuth angle correlation to determine the azimuth of said target.

Claim 18

The electronically scanned antenna according to claim 8 or 9, wherein the plurality of beams are formed in such a way that the simultaneous beams are unsymmetrical in relation to the radiation center and the interval therebetween are unequal, and target data received at unequal time intervals corresponding to said plurality of beams are processed in terms of azimuth angle correlation to determine the azimuth of said target.