Radio frequency beam forming network

• US 4,090,199 A
• Filed: 04/02/1976
• Issued: 05/16/1978
• Est. Priority Date: 04/02/1976
• Status: Expired due to Term

• Current Assignee: Raytheon Company (Rtx Corporation)
• Original Assignee: Raytheon Company (Rtx Corporation)
• Inventors: Archer, Donald H.
• Primary Examiner(s): Wilbur, Maynard R.
• Assistant Examiner(s): Berger, Richard E.
• Application Number:
  US05/673,169
• Time in Patent Office: 774 Days
• Field of Search: 343/100 R, 343/100 SA, 343/854
• US Class Current: 342/373
• CPC Class Codes: H01Q 25/007 using two or more primary active elements in the focal region of a focusing device for operation on different wavebands H01Q5/22
• CPC Class Codes: H01Q 3/2658 Phased-array fed focussing structure

Abstract

A radio frequency beam forming network is disclosed wherein a plurality of antenna feed elements arranged in the focal plane of a radio frequency lens is coupled to corresponding input ports of a radio frequency energy distributing means. Output ports of such radio frequency energy distributing means are coupled to a receiver/transmitter through different paths. Disposed in the different paths are active elements, including variable phase shifters and attenuators. The active elements, in response to control signals, provide proper attenuation and phase shift to the signals passing therethrough thereby to form a desired antenna beam. Such antenna beam is comprised of one or more "spot" beams. With such arrangements failure of a single one of the active elements will only slightly degrade system performance without resulting in a complete loss of any one of the "spot" beams.

Claims

1. A beam forming network adapted to form a plurality of beams, each one being directed along a different direction, comprising:

(a) a radio frequency lens;

(b) a plurality of radio frequency antenna feed elements disposed in the focal plane of the radio frequency lens, each one of the feed elements being associated with a corresponding one of the plurality of beams;

(c) means, having a plurality of input ports coupled to the plurality of antenna feed elements, for distributing radio frequency energy fed thereto to output ports thereof, the energy fed to any one of such input ports being distributed to the plurality of output ports with a phase distribution across such output ports being related to the one of the input ports being fed;

(d) combiner means having a plurality of input ports coupled to the output ports of the distributing means through different paths, and an output port; and

(e) means, including a plurality of active elements disposed in such different paths for providing predetermined phase shifts to the radio frequency signals passing through the different paths to maximize power transfer between ones of the plurality of feed elements and the output port selectively in accordance with control signals enabling formation of beams along directions corresponding to the beams associated with such selected ones of the feed elements.

2. The beam forming network recited in claim 1 wherein the energy distributing means includes a Butler matrix feed.

3. The beam forming network recited in claim 1 wherein the active elements include a plurality of variable phase shifters.

4. In a radio frequency communication system wherein a beam forming network is adapted to form a plurality of independent beams, each one being associated with a corresponding one of a plurality of antenna feed elements, selected ones of such beams being formed in response to control signals supplied to such beam forming network, the improvement comprising:

(a) a radio frequency lens having a focal plane, the antenna elements being disposed in such focal plane;

(b) means, coupled to the plurality of antenna feed elements, for distributing radio frequency energy applied to any one of the antenna feed elements to a plurality of outputs of such means; and

(c) means, coupled to the distributing means through a plurality of different paths, including a plurality of active elements disposed in said different paths, for maximizing the power transfer between selected ones of the plurality of antenna feed elements and the receiver/transmitter in response to said control signals, the selected ones of the plurality of feed elements forming corresponding beams along different directions.

5. The improvement recited in claim 4 wherein the distributing means includes a plurality of input ports and a plurality of output ports and means for distributing energy fed to any one of the input ports to the plurality of output ports with a phase distribution across such output ports related to the one of the input ports being fed.

6. The improvement recited in claim 5 wherein the active elements include a plurality of variable phase shifters.

7. The improvement recited in claim 6 wherein the active elements include a plurality of variable attenuators.

8. The improvement recited in claim 7 wherein the distributing means includes a Butler matrix feed.

9. A beam forming network, comprising:

(a) a radio frequency lens having a focal plane;

(b) a plurality of antenna feed elements disposed in the focal plane, each one of the feed elements being associated with a corresponding one of a plurality of beams, each beam having a different direction;

(c) means, having a plurality of input ports coupled to the plurality of antenna feed elements, and a plurality of output ports, for distributing radio frequency energy fed to any one of such input ports to the plurality of output ports;

(d) a power combiner having an output port and a plurality of input ports, such input ports being coupled to the plurality of output ports of the distributing means through different paths;

(e) a plurality of variable phase shifters disposed in the different paths; and

(f) a control signal source coupled to the plurality of phase shifters for enabling such phase shifters to provide predetermined phase shifts to the radio frequency signals passing therethrough to maximize the power transfer from selected ones of the feed elements to the output port of the power combiner to form different beams along correspondingly different directions.

10. The beam forming network recited in claim 9 including a plurality of variable attenuators disposed in the different paths and responsive to the control signal source for enabling such attenuators to provide a predetermined attenuation to the radio frequency signals passing therethrough.

11. The beam forming network recited in claim 10 wherein the distributing means includes means for distributing the radio frequency energy fed to any one of such input ports to the plurality of output ports with a phase distribution across such output ports related to the one of the input ports being fed.

12. The beam forming network recited in claim 11 wherein the distributing means includes a Butler matrix feed.

13. A beam forming network comprising:

(a) a radio frequency lens;

(b) N radio frequency feed elements disposed in the focal plane of the radio frequency lens, each one of the feed elements being associated with a corresponding one of a plurality of beams;

(c) M Butler matrices, each one having N/M input ports and N/M output ports, the input ports of the M Butler matrice being coupled to the N radio frequency feed elements, where N is greater than M;

(d) M power combiners, each one having an output port and N/M input ports, such input ports being coupled to the output ports of a corresponding one of the Butler matrices through different paths;

(e) an output power combiner having M input terminals coupled to the output ports of the M power combiners and an output terminal;

(f) a plurality of variable phase shifters disposed in the different paths; and

,

(g) a control signal source coupled to the plurality of phase shifters for enabling such phase shifters to provide predetermined phase shifts to the radio frequency signals passing therethrough to maximize the power transfer from selected ones of the feed elements to the output terminal of the output power combiner.