Coaxial cable having bimetallic outer conductor

• US 6,417,454 B1
• Filed: 06/21/2000
• Issued: 07/09/2002
• Est. Priority Date: 06/21/2000
• Status: Expired due to Fees

• Current Assignee: CommScope Inc. (CommScope Holding Company, Inc.)
• Original Assignee: CommScope Inc. (CommScope Holding Company, Inc.)
• Inventors: Biebuyck, Ghislain
• Primary Examiner(s): Nguyen, Chau N.
• Application Number:
  US09/598,508
• Time in Patent Office: 748 Days
• Field of Search: 174/102.R, 174/106.R, 174/126.1, 174/125.1, 174/126.2, 174/110.F, 174/28, 174/102.A, 333/243, 333/236
• US Class Current: 174/106.00R
• CPC Class Codes: H01B 11/1826 Co-axial cables with at least one longitudinal lapped tape-conductor

Abstract

A coaxial communications cable has a center conductor extending coaxially of the longitudinal axis of the cable with a low loss foam dielectric surrounding the inner conductor and bonded thereto. An electrically and mechanically continuous sheath surrounds the foam dielectric. The sheath is a smooth-walled longitudinally welded tube formed of a bimetallic material, which in one embodiment has an inwardly facing copper layer and an outwardly facing aluminum layer. A polymeric jacket surrounds the tubular sheath and is bonded thereto.

Claims

1. A cable comprising at least one inner conductor, a foam dielectric surrounding said at least one inner conductor, and an electrically and mechanically continuous tubular sheath formed of a bimetallic material closely surrounding said foam dielectric and being adhesively bonded thereto, said bimetallic tubular sheath including an inwardly facing copper layer bonded to said dielectric and an outwardly facing aluminum layer.

2. A cable according to claim 1 wherein said electrically and mechanically continuous tubular sheath comprises a smooth-walled longitudinally welded tube formed of said bimetallic material.

3. A cable according to claim 1, additionally including a polymer jacket surrounding said tubular sheath and bonded to said outwardly facing second metal layer.

4. A cable according to claim 1 wherein said aluminum layer is of such a thickness as to constitute more than half the overall cross sectional thickness of the bimetallic material.

5. A cable according to claim 4, wherein the wall thickness of said tubular metallic sheath is less than about 750 micrometers and said copper layer has a thickness less than 100 micrometers.

6. A cable according to claim 1 wherein said tubular bimetallic sheath has a thickness of no greater than 2.5 percent of its outer diameter.

7. A cable according to claim 1 wherein said tubular metallic sheath is adhesively bonded to said dielectric by a thin continuous adhesive layer of a thickness of about 25 micrometers or less.

8. A cable according to claim 1, wherein said at least one inner conductor comprises a copper-clad aluminum bimetallic conductor.

9. A cable according to claim 1, wherein said at least one inner conductor comprises a copper tubular member.

10. A coaxial communications cable comprising a center conductor extending coaxially of the longitudinal axis of the cable, a low loss foam dielectric surrounding the center conductor, an electrically and mechanically continuous smooth-walled tubular sheath formed of a bimetallic material closely surrounding said foam dielectric, said bimetallic tubular sheath including an inwardly facing copper layer and an outwardly facing aluminum layer metallurgically bonded to said copper layer, a thin continuous layer of adhesive disposed between said foam dielectric and said sheath and bonding the foam dielectric to said inwardly facing copper layer to form a structural composite, and a polymeric jacket surrounding said tubular sheath and bonded to said outwardly facing aluminum layer.

11. A cable according to claim 10 wherein said aluminum layer is of such a thickness as to constitute more than half the overall cross sectional thickness of the bimetallic material.

12. A cable according to claim 11, wherein the wall thickness of said tubular metallic sheath is less than 750 micrometers and said copper layer has a thickness less than 100 micrometers.

13. A cable according to claim 10 wherein said tubular bimetallic sheath has a thickness of no greater than 2.5 percent of its outer diameter.

14. A coaxial communications cable comprising a center conductor extending coaxially of the longitudinal axis of the cable and formed of a copper-clad aluminum bimetallic conductor, a low loss foam dielectric surrounding the inner conductor, an electrically and mechanically continuous smooth-walled tubular sheath formed of a bimetallic material closely surrounding said foam dielectric, said bimetallic tubular sheath including an inwardly facing copper layer and an outwardly facing aluminum layer metallurgically bonded to said copper layer, said sheath having a wall thickness of less than 500 micrometers and the wall thickness being no greater than 2.5 percent of its outer diameter, a thin continuous layer of adhesive disposed between said foam dielectric and said sheath and bonding the foam dielectric to said inwardly facing copper layer to form a structural composite, and a polymeric jacket surrounding said tubular sheath and bonded to said outwardly facing aluminum layer.

15. The coaxial cable according to claim 14 further comprising a layer of adhesive between said sheath and said protective outer jacket serving to bond the protective outer layer to the sheath.

16. A coaxial cable according to claim 14, further comprising a layer of adhesive between said center conductor and said foam dielectric serving to bond the center conductor to the dielectric.

17. A coaxial cable according to claim 14 wherein said copper layer has a thickness less than 100 micrometers.

18. A coaxial cable according to claim 17, wherein said copper layer has a thickness between 25 and 75 micrometers.

19. A coaxial communications cable comprising a center conductor extending coaxially of the longitudinal axis of the cable and formed of a copper-clad aluminum bimetallic conductor, a low loss foam dielectric surrounding the inner conductor, a layer of adhesive between said center conductor and said foam dielectric serving to bond the center conductor to the dielectric, an electrically and mechanically continuous sheath comprising a smooth-walled longitudinally welded tube formed of copper-clad aluminum closely surrounding said foam dielectric, said sheath including an inwardly facing copper layer having a thickness between 25 and 75 micrometers and an outwardly facing aluminum layer, said sheath having a wall thickness of less than 500 micrometers, a thin continuous layer of adhesive disposed between said foam dielectric and said sheath and bonding the foam dielectric to said inwardly facing copper layer to form a structural composite, a polymeric jacket surrounding said tubular sheath, and a thin layer of adhesive disposed between said sheath and said polymeric jacket and bonding said jacket to said outwardly facing aluminum layer of said sheath.