Shielded ribbon cable

Claim 1

A flexible ribbon cable having a signal portion comprising: a plurality of substantially longitudinally parallel circular conductors having a uniform diameter and lying in a single plane, said plurality of conductors having transversely uniform predetermined and longitudinally uniform cross-sectional spacing; insulation encasing said plurality of conductors having a uniform effective dielectric constant of not more than 3.0 and having two outer surfaces substantially parallel to said single plane; and a sheet conductor having a maximum resistivity of not more than 3.5 milliohms per square, said sheet conductor having two inner surfaces conforming to said two outer surfaces of said insulation, said sheet conductor being bonded to said insulation on said two outer surfaces, and said sheet conductor encasing said insulation on substantially all cross-sectional sides and providing both transverse and longitudinal electrical continuity; where the ratio of the value of the diameter of said parallel circular conductors to the value of the distance between centers of said parallel circular conductors is not less than 0.16 and not more than 0.42; and where the ratio of the value of the distance between said two inner surfaces of said sheet conductor to the value of the distance between centers of said parallel circular conductors is not more than 1.5; whereby the electrical characteristics of said signal portion of said flexible ribbon cable approximate the electrical characteristics of a coaxial cable with a comparable insulation thickness.