Composite conductor having improved high frequency signal transmission characteristics

• US 5,574,260 A
• Filed: 03/06/1995
• Issued: 11/12/1996
• Est. Priority Date: 03/06/1995
• Status: Expired due to Term

• Current Assignee: W. L. Gore & Associates (W.L. Gore & Associates)
• Original Assignee: W. L. Gore & Associates (W.L. Gore & Associates)
• Inventors: Broomall, James R., Foster, Christine M., Widdoes, Peter A., Theorin, Craig R.
• Primary Examiner(s): Kincaid, Kristine L.
• Assistant Examiner(s): Nguyen, Chau N.
• Application Number:
  US08/400,054
• Time in Patent Office: 617 Days
• Field of Search: 174/102 R, 174/106 R, 174/126.1, 174/126.2, 333/243, 333/236
• US Class Current: 174/102.00R
• CPC Class Codes: H01B 1/02 mainly consisting of metals or alloys
• CPC Class Codes: H01B 11/1808 Construction of the conductors
• CPC Class Codes: H01B 7/0009 Details relating to the conductive cores

Abstract

A composite conductor having improved high frequency signal transmission characteristics is provided which includes a conductive base and a conductive coating. The relationship between the conductivity and the permeability of the conductive base and the conductive coating is given by the following expression: ##EQU1##

Claims

1. A composite conductor having improved high frequency signal transmission characteristics comprising:

a conductive base having a permeability μ

₂ and a conductivity σ

₂ ; and

a conductive coating disposed upon the conductive base, the conductive coating having a permeability μ

₁ and a conductivity σ

₁, such that ##EQU15## wherein the conductive coating has a thickness ranging from about one-half to about five times a skin depth of said coating; and

wherein a current distribution of the composite conductor is redistributed from the conductive base to the conductive coating by employing a conductive base having a higher surface resistance than the conductive coating.

2. A composite conductor having improved high frequency signal transmission characteristics, as claimed in claim 1, wherein the conductive base is comprised of a material selected from a group consisting of iron, nickel, alloys containing iron, and alloys containing nickel.

3. A composite conductor having improved high frequency signal transmission characteristics, as claimed in claim 1, wherein the conductive coating is comprised of a material selected from a group consisting of silver, copper, gold, aluminum and tin.

4. A composite conductor having improved high frequency signal transmission characteristics, as claimed in claim 1, wherein the conductive coating has a thickness substantially equal to the skin depth.

5. A composite conductor having improved high frequency signal transmission characteristics comprising:

a material having a predetermined high thermal conductivity;

a conductive base layer disposed upon said highly thermally conductive material, the conductive base layer having a permeability μ

₂ and a conductivity σ

₂ ; and

a conductive coating layer disposed upon the conductive base layer, the conductive coating layer having a permeability μ

₁ and a conductivity σ

₁, such that ##EQU16## wherein the conductive coating has a thickness ranging from about one-half to about five times a skin depth of said coating; and

wherein a current distribution of the composite conductor is redistributed from the conductive base layer to the conductive coating layer by employing a conductive base layer having a higher surface resistance than the conductive coating layer.

6. A composite conductor having improved high frequency signal transmission characteristics, as claimed in claim 5, wherein said highly thermally conductive material is copper.

7. A composite conductor having improved high frequency signal transmission characteristics, as claimed in claim 5, wherein the conductive base layer is comprised of a material selected from a group consisting of:

iron, nickel, alloys containing iron, and alloys containing nickel.

8. A composite conductor having improved high frequency signal transmission characteristics, as claimed in claim 5, wherein the conductive coating layer is comprised of a material selected from a group consisting of:

silver, copper, gold, aluminum and tin.

9. A composite conductor having improved high frequency signal transmission characteristics, as claimed in claim 5, wherein the conductive coating layer has a thickness substantially equal to the skin depth.

10. A coaxial cable having improved high frequency signal transmission characteristics comprising:

a center conductor comprising;

a conductive base having a permeability μ

₂ and a conductivity σ

₂ ; and

a conductive coating disposed upon the conductive base, the conductive coating having a permeability μ

₁ and a conductivity σ

₁, such that ##EQU17## wherein the conductive coating has a thickness ranging from about one-half to about five times a skin depth of said coating; and

wherein a current distribution of the composite conductor is redistributed from the conductive base to the conductive coating by employing a conductive base having a higher surface resistance than the conductive coating;

a dielectric material disposed about the center conductor;

an outer conductor disposed about the dielectric material; and

an insulating jacket disposed about the outer conductor.

11. A coaxial cable as claimed in claim 10 wherein the conductive base of the center conductor is comprised of a material selected from a group consisting of iron, nickel, alloys containing iron, and alloys containing nickel.

12. A coaxial cable as claimed in claim 11 wherein the conductive coating of the center conductor is comprised of a material selected from a group consisting of silver, copper, gold, aluminum and tin.

13. A coaxial cable as claimed in claim 12 wherein the conductive coating has a thickness substantially equal to the skin depth.

14. A coaxial cable having improved high frequency signal transmission characteristics comprising:

a center conductor defined by a conductive base, and a conductive coating disposed upon the conductive base such that ##EQU18## a dielectric material disposed about the center conductor;

an outer conductor disposed about the dielectric material, the outer conductor being defined by,

a) a conductive base; and

b) a conductive coating disposed upon the conductive base such that ##EQU19## an insulating jacket disposed about the outer conductor.

15. A coaxial cable having improved high frequency signal transmission characteristics comprising:

a center conductor;

a dielectric material disposed about the center conductor;

an outer conductor disposed about the dielectric material, the outer conductor comprising;

a) a conductive base; and

b) a conductive coating disposed upon the conductive base such that ##EQU20## an insulating jacket disposed about the outer conductor.