RF feed network for modular active aperture electronically steered arrays

• US 8,427,371 B2
• Filed: 04/09/2010
• Issued: 04/23/2013
• Est. Priority Date: 04/09/2010
• Status: Active Grant

• Current Assignee: Raytheon Company (Rtx Corporation)
• Original Assignee: Raytheon Company (Rtx Corporation)
• Inventors: Pozgay, Jerome H.
• Primary Examiner(s): Issing, Gregory C
• Application Number:
  US12/757,371
• Publication Number:
  US 20110248796A1
• Time in Patent Office: 1,110 Days
• Field of Search: 342/427, 342/373, 342/384
• US Class Current: 342/373
• CPC Class Codes: G01S 13/4463 using phased arrays
• CPC Class Codes: H01Q 21/0025 Modular arrays
• CPC Class Codes: H01Q 25/02 providing sum and difference patterns H01Q25/04 takes precedence

Abstract

A feed network for an antenna subarray includes a first feed arrangement having an sum output, a second feed arrangement having an delta output, a fixed attenuator having a first port and a second port, the first port connected to the delta output of the second feed arrangement, a first power divider/combiner having a first and second port and a third port; the first port connected to the second port of the fixed attenuator, a variable phase shifter having a first port and a second port, the first port connected to the second port of the power divider/combiner, a variable attenuator having a first port and a second port, the first port connected to the second port of the variable phase shifter, a second power divider/combiner having a first and second port and a third port; the first port connected to the second port of the fixed attenuator, a first circulator having a first port, a second port and a third port, the first port connected to the sum output of the first feed arrangement, and a third power divider/combiner having a first and second port and a third port; the third port connected to the second port of the circulator and the second port connected to the second port of the variable attenuator.

Claims

1. A feed network for an antenna subarray comprising:

a first feed arrangement having a sum forming signal output;

a second feed arrangement having a delta forming signal output;

a fixed attenuator having a first port and a second port, the first port of the fixed attenuator connected to the delta forming signal output of the second feed arrangement;

a first power divider/combiner having a first and second, port and a third port;

the first port of the first power divider/combiner connected to the second port of the fixed attenuator;

a variable phase shifter having a first port and a second port, the first port of the variable phase shifter connected to the second, port of the first power divider/combiner;

a variable attenuator having a first port and a second port, the first port of the variable attenuator connected to the second port of the variable phase shifter;

a second power divider/combiner having a first and second port and a third port;

the first port divider/combiner;

connected to the second port of the fixed attenuator;

a first circulator having a first port, a second port and a third port, the first port of the first circulator connected to the sum forming signal output of the first feed arrangement and the second port of the first circulator connected to the third ort of the second power divider/combiner; and

a second circulator having a first port, a second port and a third port;

the first port of the second circulator connected to the second port of the second power divider/combiner and the second port of the second circulator connected to the third port of the first circulator.

2. The feed network for an antenna subarray as recited in claim 1 further comprising a plurality of couplers, each one of the plurality of couplers having an antenna port, a sum port, a delta port and a termination port, the sum port of each one of the plurality of couplers connected to the first feed arrangement.

3. The feed network for an antenna subarray a recited in claim 2 wherein the delta port of each one of the plurality of couplers is connected to the second feed arrangement.

4. The feed network for an antenna subarray as recited in claim 1 wherein a coupling value for each one of the plurality of hybrid couplers is derived from the formula:

5. The feed network for an antenna subarray as recited in claim 4 wherein the coupling value is derived the

6. The feed network for an antenna subarray as recited in claim 4 wherein the attenuation value of the variable attenuator is derived from the

7. The feed network for an antenna subarray as recited in claim 4 wherein the phase shift value of the variable phase shifter is derived from the

8. A feed network for an antenna subarray comprising;

a plurality of couplers, each one of the plurality of couplers having an antenna port, a sum port, a delta port and a termination port;

a first feed arrangement connected to each one of the sum ports of the plurality of couplers, the first feed arrangement having a sum forming signal output;

a second feed arrangement connected to each one of the delta ports of the plurality of couplers, the second feed arrangement having a delta forming signal output;

a fixed attenuator having a first port and a second port, the first port of the fixed attenuator connected to the delta forming signal output of the second feed arrangement;

a first power divider/combiner having a first and second port and a third port;

the first port of the first power divider/combiner connected to the second port of the fixed attenuator;

a variable phase shifter having a first port and a second port, the first port of the variable phase shifter connected to the second port of the first power divider/combiner;

a variable attenuator having a first port and a second port, the first port of the variable attenuator connected to the second port of the variable phase shifter;

a second power divider/combiner having a first and second port and a third port;

the first port of the second power divider/combiner connected to the second port of the fixed attenuator;

a first circulator having a first port, a second port and a third port, the first port of the first circulator connected to the sum forming signal output of the first feed arrangement and the second port of the first circulator connected to the third port of the second power divider/combiner; and

a second circulator having a first port, a second port and a third port;

the first port of the second circulator connected to the second port of the second power divider/combiner and the second port of the second circulator connected to the third port of the first circulator.

9. An antenna subarray comprising:

a plurality of radiators;

a plurality of transmit-receive modules, each one of the transmit-receive modules coupled to a respective one of the plurality of radiators;

a plurality of RF couplers, each one connected to a respective one of said plurality of transmit-receive modules;

a first feed arrangement of uniform power dividers coupled to said plurality of RF couplers;

a second feed arrangement of uniform power dividers coupled to said plurality of RF couplers;

a first circulator having a feed port, a transmit port and a sum port, the feed port of the first circulator connected to said first feed arrangement;

a second circulator having a feed port, a transmit port and a sum port, the transmit port of the second circulator connected to the transmit port of the first circulator;

a first power divider/combiner having a first and second port and a third port;

a second power divider/combiner having a first and a second port and a third port, the third port of the second power divider/combiner connected to the sum port of the first circulator and the second port of the second power divider/combiner connected to the sum port of the second circulator;

a variable attenuator having a first and a second port, the second port of the variable attenuator connected to the first port of the second power divider/combiner;

a variable phase shifter having a first and a second port, the second port of the variable phase shifter connected to the first port of the variable attenuator and the first port of the variable phase shifter connected to the second port of the first power divider/combiner;

a fixed attenuator having a first and a second port, the first port of the fixed attenuator connected to the second feed arrangement and the second port of the fixed attenuator connected to the first port of the first power divider/combiner.

10. The antenna subarray as recited in claim 9 wherein said variable attenuator is adjusted to a value in accordance with a location of the antenna subarray within an active aperture electronically steered array.

11. The antenna subarray as recited in claim 9 wherein each one of the plurality of RF couplers comprises a four port coupler.

12. The antenna subarray as recited in claim 9 wherein said plurality of radiators comprises eight radiators and said plurality of transmit-receive modules comprise eight transmit-receive modules.