Low backscatter polymer antenna with graded conductivity

• US 20060125707A1
• Filed: 12/10/2004
• Published: 06/15/2006
• Est. Priority Date: 12/10/2004
• Status: Active Grant

• Current Assignee: Cobham Advanced Electronic Solutions, Inc. (Cobham PLC)
• Original Assignee: BAE Systems Information and Electronic Systems Integration Incorporated (BAE Systems Plc)
• Inventors: Waschenko, Donald P.
• Granted Patent: US 7,236,139 B2
• Time in Patent Office: Days
• US Class Current: 343/790
• CPC Class Codes: H01Q 1/362 for broadside radiating helical antennas
• CPC Class Codes: H01Q 1/364 using a particular conducting material, e.g. superconductor
• CPC Class Codes: H01Q 11/08 Helical antennas
• CPC Class Codes: H01Q 13/08 Radiating ends of two-conductor microwave transmission lines, e.g. of coaxial lines, of microstrip lines
• CPC Class Codes: H01Q 21/06 Arrays of individually energised antenna units similarly polarised and spaced apart
• CPC Class Codes: H01Q 9/28 Conical, cylindrical, cage, strip, gauze, or like elements having an extended radiating surface; Elements comprising two conical surfaces having collinear axes and adjacent apices and fed by two-conductor transmission lines waveguide horns or mouths H01Q13/00; slot antennas H01Q13/00

Abstract

Polymer antenna structures having low reflectivity and high efficiency are disclosed. Wire antennas can be configured from coaxial cable having center conductors and outer conductors made from conductive polymer. Fabrics can also be configured with conductive polymer antenna elements formed in or on the fabric. The conductive polymer antenna elements can be configured with a graded conductivity to facilitate capture (as opposed to reflection) of electromagnetic energy.

Claims

1. A low backscatter antenna having a conductive element for at least one of receiving and radiating information, the antenna comprising:

a conductive polymer center conductor having an exposed portion that forms at least a portion of the conductive element of the antenna and has a graded conductivity ranging from relatively low conductivity at its perimeter to relatively high conductivity at its center.

2. The antenna of claim 1 further comprising:

a dielectric layer covering the unexposed portion of the conductive polymer to provide an insulating spacer; and

an outer conductive polymer layer around the dielectric layer.

3. The antenna of claim 2 wherein the outer conductive polymer layer is in the form of a braid or an outer conductive jacket.

4. The antenna of claim 2 wherein the antenna is a dipole antenna formed from the exposed portion of the center conductor and an additional one or more strands of conductive polymer that is electrically coupled to the outer conductive polymer layer.

5. The antenna of claim 1 wherein conductive polymer center conductor is comprised of a plurality of conductive polymer strands, with strands at the perimeter having the lower conductivity and strands at the center having the higher conductivity.

6. The antenna of claim 1 wherein conductive polymer center conductor is comprised of a plurality of conductive polymer strands, with strands at the perimeter being coated with a conductive polymer layer having lower conductivity relative to conductivity of the strands themselves, thereby providing the graded conductivity.

7. The antenna of claim 1 wherein conductive polymer center conductor is a single strand of conductive polymer that is coated with a conductive polymer layer having lower conductivity relative to conductivity of the strand itself, thereby providing the graded conductivity.

8. The antenna of claim 1 wherein the antenna includes a balun.

9. A low backscatter antenna having a conductive element for at least one of receiving and radiating information, the antenna comprising:

a plurality of nonconductive strands interweaved with one another; and

one or more conductive polymer strands interweaved with the nonconductive strands so as to provide one or more conductive elements of the antenna.

10. The antenna of claim 9 wherein each of the one or more conductive elements of the antenna has a graded conductivity ranging from relatively low conductivity at its outer surface to relatively high inner conductivity.

11. The antenna of claim 9 wherein the antenna further includes one or more feed circuits operatively coupled to respective conductive polymer strands.

12. The antenna of claim 9 wherein there are N conductive polymer strands and the antenna is configured as an N/2 element dipole array.

13. The antenna of claim 12 wherein each of the N conductive polymer strands is operatively coupled to a feed circuit.

14. The antenna of claim 12 wherein a fabric formed by the nonconductive strands and the conductive polymer strands has a first side and a second side, and the conductive elements are on both sides.

15. A low backscatter antenna having a conductive element for at least one of receiving and radiating information, the antenna comprising:

a plurality of nonconductive strands formed into a fabric; and

one or more conductive polymer coatings on the fabric so as to provide one or more conductive elements of the antenna.

16. The antenna of claim 15 wherein each of the one or more conductive elements of the antenna has a graded conductivity ranging from relatively low conductivity at its outer surface to relatively high inner conductivity.

17. The antenna of claim 15 wherein the antenna further includes one or more feed circuits operatively coupled to respective conductive elements of the antenna.

18. The antenna of claim 15 wherein at least one of the conductive elements of the antenna has a shape defined by boundaries that are not parallel to the nonconductive strands.

19. The antenna of claim 18 wherein there are N conductive elements and the antenna is configured as an N/2 element bow-tie array.

20. The antenna of claim 15 wherein the fabric has a first side and a second side, and the conductive elements are on both sides.

21. A fabric having graded conductivity comprising:

a plurality of nonconductive strands formed into a fabric; and

one or more conductive polymer strands or coatings formed into or on the fabric, so as to provide one or more conductive regions of the fabric;

wherein each of the one or more conductive regions has a graded conductivity ranging from relatively low conductivity at its outer surface to relatively high inner conductivity.