Multipair differential signal transmission cable

1. A multipair differential signal transmission cable, comprising:

a plurality of differential signal transmission cables being bundled and each comprising two signal conductors as a differential pair covered with an insulation and a first shielding tape conductor provided therearound,

wherein the first shielding tape conductor is longitudinally lapped so as to include an overlapping portion in a cable longitudinal direction such that the overlapping portion is located on a perpendicular line passing through substantially a middle of a line connecting the two signal conductors,

wherein the plurality of differential signal transmission cables comprise at least one or more pairs of two adjacent differential signal transmission cables, and

wherein two of the differential signal transmission cables are arranged in a middle of the multipair differential signal transmission cable as viewed in a cross section such that the overlapping portion faces toward an outside of the multipair differential signal transmission cable;

an inclusion layer encircling the two of the differential signal transmission cables, wherein six of the differential signal transmission cables are arranged therearound via the inclusion layer such that the overlapping portion faces toward the outside of the multipair differential signal transmission cable; and

an insulation tape covering a periphery of the first shielding tape conductor,

wherein the multipair differential signal transmission cable is configured for high-speed transmission at a level of not less than 10 Gbps, and

wherein a vacant space is provided between the insulation tape and the first shielding tape conductor.

2. The multipair differential signal transmission cable according to claim 1 , wherein the differential signal transmission cables are arranged so that the overlapping portion of each of the plurality of differential signal transmission cables faces the outside of the multipair differential signal transmission cable.

3. The multipair differential signal transmission cable according to claim 1 , wherein the differential signal transmission cables are arranged so that the overlapping portion of all of the plurality of adjacent differential signal transmission cables faces the outside of the multipair differential signal transmission cable.

4. The multipair differential signal transmission cable according to claim 1 , wherein the differential signal transmission cable does not include a drain wire, and

wherein the two signal conductors are covered all together with the insulation having a shape that does not create a gap from the first shielding tape conductor.

5. The multipair differential signal transmission cable according to claim 1 , wherein the two signal conductors are covered all together with the insulation having a flat oval cross-sectional shape that comprises flat portions parallel to an arrangement direction of the two signal conductors.

6. The multipair differential signal transmission cable according to claim 1 , wherein the two signal conductors are covered all together with the insulation having an ellipse cross-sectional shape that is long in an arrangement direction of the two signal conductors.

7. The multipair differential signal transmission cable according to claim 1 , wherein the inclusion layer is arranged in the middle of the multipair differential signal transmission cable as viewed in a cross section, and

wherein eight of the differential signal transmission cables are arranged around the inclusion layer.

8. The multipair differential signal transmission cable according to claim 1 , further comprising:

a second shielding tape conductor wrapping the plurality of differential signal transmission cables all together;

a braided wire covering a periphery of the second shielding tape conductor; and

a jacket covering the braided wire.

9. The multipair differential signal transmission cable according to claim 1 , wherein the at least one or more pairs of two adjacent differential signal transmission cables is disposed in a circumferential direction of the multipair differential signal transmission cable, and

wherein the two adjacent differential signal transmission cables are arranged such that the overlapping portion of one of the two adjacent differential signal transmission cables does not face another of the two adjacent differential signal transmission cables.

10. The multipair differential signal transmission cable according to claim 1 , further comprising:

sixteen differential signal transmission cables arranged around the six differential signal transmission cables via another inclusion layer.

11. The multipair differential signal transmission cable according to claim 1 , wherein a leakage of electromagnetic energy from a surface of the first shielding tape conductor that includes the overlapping portion is larger than the leakage of electromagnetic energy from a surface of the first shielding tape conductor opposite to the surface of the first shielding tape conductor that includes the overlapping portion.

12. The multipair differential signal transmission cable according to claim 11 , wherein an amount of electromagnetic energy contributing to a crosstalk is different between the surface of the first shielding tape conductor that includes the overlapping portion and the surface of the first shielding tape conductor opposite to the surface of the first shielding tape conductor that includes the overlapping portion.

13. The multipair differential signal transmission cable according to claim 1 , wherein the inclusion layer is disposed between the six of the differential signal transmission cables and the two of the differential signal transmission cables.

14. The multipair differential signal transmission cable according to claim 1 , wherein the inclusion layer comprises a foamed polyolefin layer.

15. The multipair differential signal transmission cable according to claim 1 , wherein a length of the overlapping portion is less than a distance between the two signal conductors.

16. The multipair differential signal transmission cable according to claim 15 , wherein, in the overlapping portion, a bottom surface of the first shielding tape conductor extends above an upper surface of the first shielding tape conductor.

17. The multipair differential signal transmission cable according to claim 1 , wherein the overlapping portion is arranged in a twisted manner in which a bottom surface of the first shielding tape conductor extends above an upper surface of the first shielding tape conductor.

18. The multipair differential signal transmission cable according to claim 1 , wherein the vacant space extends from an edge of the overlapping portion to a lower surface of the insulation tape.

19. The multipair differential signal transmission cable according to claim 18 , wherein the vacant space further extends from the edge of the overlapping portion to an upper surface of the first shielding tape conductor.

20. The multipair differential signal transmission cable according to claim 1 , wherein a gap is provided between an inner edge of the insulation tape and an outer edge of the first shielding tape conductor.