Shielded cable assemblies

• US 5,393,928 A
• Filed: 02/19/1993
• Issued: 02/28/1995
• Est. Priority Date: 02/19/1993
• Status: Expired due to Term

• Current Assignee: Laird Technologies Incorporated (DuPont de Nemours, Inc.)
• Original Assignee: Monsanto Company (Bayer AG)
• Inventors: Wohl, Martin H., Henn, Arthur R., Cribb, Richard M.
• Primary Examiner(s): NIMMO, MORRIS
• Application Number:
  US08/021,504
• Time in Patent Office: 739 Days
• Field of Search: 174/36, 174/35 R, 174/117 M, 174/109
• US Class Current: 174/36
• CPC Class Codes: H01B 11/1033 composed of a wire-braided conductor
• CPC Class Codes: Y10T 442/3398 Vapor or sputter deposited metal layer
• CPC Class Codes: Y10T 442/3407 Chemically deposited metal layer [e.g., chemical precipitation or electrochemical deposition or plating, etc.]
• CPC Class Codes: Y10T 442/657 Vapor, chemical, or spray deposited metal layer

Abstract

Lower weight shielded cable assemblies with an enhanced level of shielding effectiveness, e.g. in the range of 0.1 MHz to 20 GHz, comprising a core of at least one insulated conductor element overwrapped with metallized fabric, e.g. characterized as having a surface resistivity less than 100 milliohms/square or as being a metallized fabric coated with at least a layer of copper having a metal density of greater than 50 grams/square meter. Cable assemblies can employ a shielding subassembly comprising braided wire and one or more layers of copper-metallized fabric where the shielding subassembly has a transfer impedance at 10 MHz of less than 50 mo/m. For example, it has been found that cable assemblies employing a four layer wrap of certain metallized fabrics can provide up to 20 decibels improvement in shielding effectiveness over a wide range of frequencies with a 74 percent reduction in weight compared to a standard wire braid/foil laminate shield.

Claims

1. An elongated shielded cable assembly comprising a core of at least one insulated conductor element overwrapped with more than one layer of metallized fabric, wherein said fabric has a surface resistivity less than 100 milliohms/square.

2. A shielded cable assembly according to claim 1 wherein said fabric has a surface resistivity less than 50 milliohms/square.

3. A shielded cable assembly according to claim 2 wherein said fabric has a surface resistivity less than 30 milliohms/square.

4. A shielded cable assembly according to claim 3 wherein said fabric has a surface resistivity less than 20 milliohms/square.

5. A shielded cable assembly according to claim 4 wherein said fabric has a surface resistivity less than 10 milliohms/square.

6. A shielded cable assembly according to claim 5 wherein said fabric has a surface resistivity less than 5 milliohms/square.

7. A shielded cable assembly comprising a core of at least one insulated conductor element overwrapped with more than one layer of metallized fabric, wherein said fabric is coated with at least a layer of copper having a metal density of greater than 50 grams per square meter.

8. A shielded cable assembly according to claim 7 wherein said fabric is coated with at least a layer of copper having a metal density of greater than 70 grams per square meter.

9. A shielded cable assembly according to claim 8 wherein said fabric is coated with at least a layer of copper having a metal density of greater than 100 grams per square meter.

10. A shielded cable assembly according to claim 9 wherein said fabric is coated with at least a layer of copper having a metal density of greater than 200 grams per square meter.

11. A shielded cable assembly according to claim 10 wherein said fabric is coated with at least a layer of copper having a metal density of greater than 300 grams per square meter.

12. A shielded cable assembly comprising a core of at least one insulated conductor element overwrapped a shielding subassembly comprising braided wire exhibiting transfer-impedance of less than 50 milliohms/meter at 0.2 MHz and one or more layers of copper-metallized fabric selected so that the shielding subassembly has a transfer impedance at 10 MHz of less than 50 milliohms/meter.

13. A shielded cable assembly according to claim 12 wherein said subassembly has a transfer impedance at 10 MHz of less than 25 milliohms/meter.

14. A shielded cable assembly according to claim 13 wherein said subassembly has a transfer impedance at 10 MHz of less than 10 milliohms/meter.

15. A shielded cable assembly according to claim 14 wherein said subassembly has a transfer impedance at 10 MHz of less than 5 milliohms/meter.

16. A shielded cable assembly according to claim 15 wherein said subassembly has a transfer impedance at 10 MHz of less than 2 milliohms/meter.

17. Metallized fabric having at least one layer of metal on a fibrous substrate, said fabric being selected from the group consisting of (a) woven fabric having a surface resistivity less than 20 milliohms/square, (b) non-woven fabric having a surface resistivity less than 50 milliohms/square and (c) woven or non-woven fabric having at least one layer of copper and a metal density greater than 50 grams/square meter.

18. Metallized fabric according to claim 17 wherein said at least one layer of metal comprises a layer of copper coated with a layer of nickel, silver or tin and wherein said layer of copper is at least 25 percent by weight of the metal on said fabric.

19. A metallized fabric according to claim 17 wherein said fabric is a woven fabric having a surface resistivity of less than 10 milliohms/square.

20. A metallized fabric according to claim 19 wherein said fabric is a woven fabric having a surface resistivity of less than 5 milliohms/square.

21. A metallized fabric according to claim 18 wherein said fabric is a woven fabric having a surface resistivity of less than 10 milliohms/square.

22. A metallized fabric according to claim 21 wherein said fabric is a woven fabric having a surface resistivity of less than 5 milliohms/square.

23. A metallized fabric according to claim 17 wherein said fabric is a nonwoven fabric having a surface resistivity of less than 30 milliohms/square.

24. A metallized fabric according to claim 23 wherein said fabric is a nonwoven fabric having a surface resistivity of less than 20 milliohms/square.

25. A metallized fabric according to claim 24 wherein said fabric is a nonwoven fabric having a surface resistivity of less than 10 milliohms/square.

26. A metallized fabric according to claim 25 wherein said fabric is a nonwoven fabric having a surface resistivity of less than 5 milliohms/square.

27. A metallized fabric according to claim 18 wherein said fabric is a nonwoven fabric having a surface resistivity of less than 30 milliohms/square.

28. A metallized fabric according to claim 27 wherein said fabric is a nonwoven fabric having a surface resistivity of less than 20 milliohms/square.

29. A metallized fabric according to claim 28 wherein said fabric is a nonwoven fabric having a surface resistivity of less than 10 milliohms/square.

30. A metallized fabric according to claim 29 wherein said fabric is a nonwoven fabric having a surface resistivity of less than 5 milliohms/square.

31. A metallized fabric according to claim 17 wherein said fabric has at least one layer of copper and a metal density greater than 70 grams/square meter.

32. A metallized fabric according to claim 31 wherein said fabric has at least one layer of copper and a metal density greater than 100 grams/square meter.

33. A metallized fabric according to claim 32 wherein said fabric has at least one layer of copper and a metal density greater than 200 grams/square meter.

34. A metallized fabric according to claim 33 wherein said fabric has at least one layer of copper and a metal density greater than 300 grams/square meter.