Low-torque microwave coaxial cable with graphite disposed between shielding layers

• US 5,194,838 A
• Filed: 11/26/1991
• Issued: 03/16/1993
• Est. Priority Date: 11/26/1991
• Status: Expired due to Fees

• Current Assignee: W. L. Gore & Associates (W.L. Gore & Associates)
• Original Assignee: W. L. Gore & Associates (W.L. Gore & Associates)
• Inventors: Cobo, Bruce R.
• Primary Examiner(s): Dzierzynski, Paul M.
• Assistant Examiner(s): Lee, Benny T.
• Application Number:
  US07/797,851
• Time in Patent Office: 476 Days
• Field of Search: 333/243, 333/236, 174/28, 174/36, 174/102 P
• US Class Current: 333/243
• CPC Class Codes: H01B 11/1813 Co-axial cables with at least one braided conductor
• CPC Class Codes: H01B 11/1878 Special measures in order to improve the flexibility
• CPC Class Codes: H01B 13/221 filling-up interstices

Abstract

A low-torque microwave cable in which interior metal layers are coated with graphite particles and a process for coating the interior layers with graphite while flexing the cable to reduce stiffness by two-thirds.

Claims

1. A microwave coaxial cable having low resistance to torque comprising:

(a) a metal center conductor surrounded by a polymeric dielectric insulation;

(b) a layer of conductive metal shielding surround said dielectric insulation;

(c) a layer of braided metal shielding surrounding said conductive shielding; and

(d) a layer of protective polymeric jacketing surrounding said braided shielding;

(e) particles of graphite being positioned between the conductive metal shielding layer and the braided shielding layer on metal surfaces thereof.

2. A cable of claim 1 wherein said dielectric polymer insulation comprises expanded polytetrafluoroethylene.

3. A cable of claim 2 wherein said layer of conductive shielding comprises helically wound silver-plated copper foil.

4. A cable of claim 1 wherein said layer of conductive metal shielding comprises metal coated polymer tape.

5. A cable of claim 1 wherein said braided metal shielding comprises braided silver-plated metal strands.

6. A cable of claim 5 wherein the metal in said silver-plated metal is selected from the group consisting of copper, steel, and copper clad steel.

7. A cable of claim 3 wherein said center conductor, said layer of conductive shielding, and said braided metal shielding comprises silver-plated copper.