Passive anti-jamming antenna system

• US 8,077,104 B1
• Filed: 11/14/2007
• Issued: 12/13/2011
• Est. Priority Date: 02/01/2000
• Status: Expired due to Fees

• Current Assignee: Leidos, Inc. (Leidos Holdings, Inc.)
• Original Assignee: Science Applications International Corporation
• Inventors: Fox, Cordell, Wing, Kevin, Murphy, Robert A., Priester, David C.
• Primary Examiner(s): DINH, TRINH VO
• Application Number:
  US11/984,165
• Time in Patent Office: 1,490 Days
• Field of Search: None
• US Class Current: 343/782
• CPC Class Codes: H01Q 1/42 Housings not intimately mechanically associated with radiating elements, e.g. radome
• CPC Class Codes: H01Q 1/526 Electromagnetic shields
• CPC Class Codes: H01Q 1/528 reducing the re-radiation of a support structure in a parabolic reflector antenna H01Q19/023
• CPC Class Codes: H01Q 17/00 Devices for absorbing waves radiated from an antenna; Combinations of such devices with active antenna elements or systems
• CPC Class Codes: H01Q 21/20 the units being spaced along or adjacent to a curvilinear path slotted waveguide arrays H01Q21/005; circularly or helically slotted waveguides H01Q21/0062
• CPC Class Codes: H01Q 3/24 varying the orientation by switching energy from one active radiating element to another, e.g. for beam switching
• CPC Class Codes: H04B 7/0491 using two or more sectors, i.e. sector diversity
• CPC Class Codes: H04B 7/086 using weights depending on external parameters, e.g. direction of arrival [DOA], predetermined weights or beamforming
• CPC Class Codes: H04K 2203/32 including a particular configuration of antennas
• CPC Class Codes: H04K 3/228 Elimination in the received signal of jamming or of data corrupted by jamming interference suppression in receivers H04B1/10

Abstract

System and method for improving the interference resistance of an radio frequency (RF) antenna system through passive prescreening of the RF energy incident upon the antenna. The invention physically partitions the RF environment into two or more sectors with respect to the direction of arrival of incident energy. The power level of the RF frequencies of interest incident upon each sector is determined such that whenever the power level exceeds a given threshold, the received signal from energy incident on that sector is modified.

Claims

1. In an environment comprising a plurality of sources of electromagnetic energy, an antenna system comprising:

a plurality of receiving antenna elements;

a partitioning structure;

positioned between the elements and the sources,

disposed to create at least two non-identical radio frequency fields of view; and

at least one absorber substantially lining at least one wall of the partitioning structure, the at least one absorber having a predetermined index of refraction that is different from a predetermined index of refraction of the at least one wall.

2. The antenna system according to claim 1, further comprising:

a processing unit;

in electrical communication with at least two antenna elements;

operative to receive the electrical signal of each communicated antenna element;

operative to characterize the electrical signal of each communicated antenna element; and

operative to modify those electrical signals for which the characterization meets a condition.

3. The antenna system according to claim 2, wherein the characterization of the electrical signal of each communicated antenna element comprises a function of the power such electrical signal.

4. The antenna system according to claim 3, wherein the condition for modification is that the function of the power of the characterized electrical signal exceeds a threshold.

5. The antenna system according to claim 4, wherein the modification of those electrical signals for which power is greater than a threshold is attenuation.

6. The antenna system according to claim 5, wherein the modification of those electrical signals for which power is greater than a threshold is blocking.

7. The antenna system according to claim 2, further comprising, a combiner:

in electrical communication with at the processing unit; and

operative to receive at least two electrical signals from the processing unit and combine the signals.

8. The antenna system according to claim 1, further comprising an outer skin substantially covering at least a portion of the partitioning structure.

9. The antenna system according to claim 8, wherein the outer skin is a bandpass filter.

10. The antenna system according to claim 1, wherein the partitioning structure comprises a plurality of hex-shaped walls.

11. In an antenna system comprising a plurality of antenna elements, a method for improving the resistance of the antenna system to interference from electromagnetic energy sources, the method comprising:

physically partitioning, using a partitioning structure, the space between the receiving antenna array and the electromagnetic energy sources such that at least two antenna elements are characterized by nonidentical radio frequency fields of view; and

substantially coating at least one surface of the partitioning structure with an absorber, the at least one absorber having a predetermined index of refraction that is different from a predetermined index of refraction of the partitioning structure.

12. The method according to claim 11, further comprising:

in response to electromagnetic energy incident on the antenna array, determining which array elements contain energy characteristic of interference; and

modifying the signal from at least one array element that contains energy characteristic of interference.

13. The method according to claim 12, wherein the step of modification comprises broadband attenuation of the signal from at least one antenna element that contains energy characteristic of interference.

14. The method according to claim 12, wherein the step of modification comprises blocking the electromagnetic energy from at least one antenna element that contains energy characteristic of interference.