Array antennas with independent sum and difference excitations levels
AssigneeBAE Systems Information and Electronic Systems Integration Inc.
InventorAlfred R. Lopez
Life of this patent
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Abstract
Improved punch-through performance is provided for applications such as sum and difference mode processing for IFF and other applications. With an array including a row of elements, difference sidelobe levels are increased relative to sum sidelobe levels by independently controlling relative signal levels of difference mode signals provided from signals received by central elements of the array. By processing signals from central elements independently from processing of signals from outer elements of the array, difference mode signals derived from the central elements may be employed at higher signal levels in order to raise difference mode sidelobe levels to improve punch-through performance. Antenna systems and methods are described.
Claims10
A method to prevent punch-through in monopulse signal reception, for use with an array antenna having a row of radiating elements including left outer elements, at least one left central element, at least one right central element and right outer elements, the method comprising the steps of:
- (a) receiving signals via said elements;
- (b) forming an outer sum signal and an outer difference signal by processing signals received via the left outer elements and right outer elements;
- (c) forming a central sum signal and a central difference signal by processing signals received via the at least one left central element and at least one right central element;
- (d) combining said outer sum and central sum signals provided in steps (b) and (c) at predetermined relative signal levels to form a composite sum signal;
- (e) combining said outer difference and central difference signals provided in steps (b) and (c) at predetermined relative signal levels to form a composite difference signal;
- and
- (f) implementing step (e) with the central difference signal combined at a higher signal level which is higher, on a per element basis, than the relative signal level of each of the outer sum, outer difference and central sum signals, thereby providing punch-through avoidance.
An array antenna system configured to prevent punch-through in monopulse signal reception, comprising:
- an array (42) comprising a row of radiating elements including a plurality of left outer elements (44), at least one left central element (46), at least one right central element (48), and a plurality of right outer elements (50);
- a first circuit device (52) coupled to said left and right outer elements (44, 50) and arranged to provide at a first sum port (53) an outer sum signal and at a first difference port (54) an outer difference signal;
- a second circuit device (56) coupled to said left and right central elements (46, 48) and arranged to provide at a second sum port (57) a central sum signal and at a second difference port (58) a central difference signal;
- a first power divider/combiner (60) coupled to said first and second sum ports (53, 57) and configured to provide at a sum signal output port (61) a composite sum signal formed by combining said outer sum and central sum signals, each combined at a predetermined relative signal level;
- and
- a second power divider/combiner (62) coupled to said first and second difference ports (54, 58) and configured to provide at a difference signal output port (63) a composite difference signal formed by combining said outer difference and central difference signals, the outer difference signal combined at a predetermined relative signal level and the central difference signal combined at a higher signal level which is higher, on a per element basis, than said relative signal level of each of the outer sum, outer difference and central sum signals;
- said higher signal level of the central difference signal predetermined to provide punch-through avoidance.
Dependencies are inferred from the claim text.