Patent ID: 8546691

Claim:
A differential signal transmission cable, comprising: a pair of differential signal lines arranged in parallel to each other; an insulation for bundle-covering the pair of differential signal lines; and a shield conductor wound around an outer periphery of the insulation, wherein the insulation is configured such that an outer circumference thereof in a cross section perpendicular to a longitudinal direction thereof has an oval shape formed with a continuous convex arc-curve, wherein the outer circumference of the insulation comprises a first curved portion with a pair of symmetrical elliptical arcs located at both ends in a first direction along the arrangement direction of the pair of differential signal lines and a second curved portion with a pair of symmetrical elliptical arcs located at both ends in a second direction orthogonal to the first directional, and wherein the cable satisfies a condition represented by the following formula (1) where a minor or major axis of the elliptical arc of the first curved portion in the first direction is 2 a 1 , a major or minor axis of the elliptical arc of the first curved portion in the second direction is 2 b 1 , a major axis of the elliptical arc of the second curved portion in the first direction is 2 b 2 , a minor axis of the elliptical arc of the second curved portion in the second direction is 2 b 2 , a phase angle of a connecting point between the elliptical arc of the first curved portion and the second curved portion is θ 0 and a phase angle of a connecting point between the elliptical arc of the second curved portion and the first curved portion is φ 0 , tan ⁢ ⁢ ϕ 0 = a 1 ⁢ b 2 a 2 ⁢ b 1 ⁢ tan ⁢ ⁢ θ 0 . formula ⁢ ⁢ ( 1 )