Multi-layered, shielded and grounded cables and related methods
Data/telecommunication cables that include one or more layers of an integral, bonded electromagnetic shield are described. The shield may be configured to form an electrical ground path.
1. A grounded and shielded cable configured to absorb high frequency components of interfering signals comprising:
one or more core conductors;
insulation surrounding the one or more core conductors;
an electromagnetic shield comprising at least (i) one or more outer conductive shield layers composed of a first material composition, (ii) one or more inner insulating layers, and (iii) one or more inner conductive shield layers composed of a second material composition, wherein:
the second material composition is dissimilar to the first material composition;
the electromagnetic shield is wrapped around the insulation such that the one or more inner conductive shield layers of the first material composition electrically contact the one or more outer conductive shield layers of the second material composition over an overlapped portion of the electromagnetic shield and form an electrical ground return path; and
the electromagnetic shield is configured to create a local, coupling capacitance between the one or more outer conductive shield layers and the one or more inner conductive shield layers to electromagnetically shield the one or more core conductors from the interfering signals;
an outer insulating layer; and
an adhesive layer between the outer insulating layer and the electromagnetic shield, the adhesive layer comprising a plurality of separated, diamond-shaped sections.
2. The cable as in claim 1 wherein the cable comprises a twinax cable.
3. The cable as in claim 1 wherein the outer insulating layer and the one or more of the inner insulating layers are composed of a Mylar or polyethylene terephthalate material.
4. The cable as in claim 1 wherein the first material composition comprises a copper material.
5. The cable as in claim 4 wherein the second material composition comprises an aluminum material.
6. The cable as in claim 5 wherein the aluminum in the one or more inner conductive shield layers has a thickness of 9 μm.
7. The cable as in claim 4 wherein the copper in the one or more outer conductive shield layers has a thickness of 9 μm.
8. The cable as in claim 1 wherein the outer insulating layer comprises two layers, and each of the layers has a thickness of 12 μm.
9. The cable as in claim 1 wherein the outer insulating layer comprises a single layer and has a thickness of 12 μm.
10. The cable as in claim 1 wherein the electromagnetic shield comprises an integral, bonded component.
11. The cable as in claim 1 wherein the electromagnetic shield is wrapped longitudinally around the insulation.
12. The cable as in claim 1 wherein the electromagnetic shield is wrapped helically around the insulation.
13. The cable as in claim 1 wherein:
the electromagnetic shield is wrapped around the insulation at an angle of more than 360 degrees; and
the overlapped portion is configured to provide a direct electrical connection between the one or more inner conductive shield layers and the one or more outer conductive shield layers.
14. The cable as in claim 13 wherein the overlapped portion comprises a length equal to 20% to 70% of a circumference of the electromagnetic shield measured around the insulation surrounding the one or more core conductors.
15. The cable as in claim 13 wherein the overlapped portion comprises a length that is 50% of a circumference of the electromagnetic shield measured around the insulation surrounding the one or more core conductors.
16. The cable as in claim 1 wherein the one or more outer conductive shield layers and one or more inner conductive shield layers are configured to make direct galvanic contact over the overlapped portion of the electromagnetic shield to form the electrical ground return path.
17. The cable as in claim 1 wherein:
the electromagnetic shield is wrapped longitudinally around the insulation; and
the outer insulating layer comprises a first outer insulating layer and a second outer insulating layer.
18. A grounded and shielded cable comprising:
one or more core conductors;
insulation surrounding the one or more core conductors;
an electromagnetic shield comprising one or more outer conductive shield layers, one or more inner insulating layers, and one or more inner conductive shield layers, wherein:
the one or more outer conductive shield layers comprise copper;
the one or more inner conductive shield layers comprise aluminum; and
the electromagnetic shield is wrapped around the insulation such that the one or more inner conductive shield layers comprising aluminum electrically contact the one or more outer conductive shield layers comprising copper over an overlapped portion of the electromagnetic shield and form an electrical ground return path;
an outer insulating layer around the electromagnetic shield; and
an adhesive layer between the outer insulating layer and the electromagnetic shield, the adhesive layer comprising a plurality of separated, diamond-shaped sections.
19. The cable as in claim 18 wherein the electromagnetic shield is wrapped longitudinally around the insulation.
20. The cable as in claim 18 wherein the electromagnetic shield is wrapped helically around the insulation.