Electrical cables and optical waveguides are disclosed as including an electrically insulative foam. The electrically insulative foam can coat at least one electrical conductor of the electrical cable. The electrically insulative foam can coat the optical fiber of the waveguide. The electrically insulative foam can also define a waveguide.

To provide a coaxial cable with a favorable appearance and excellent processability. The above-described problem is solved by a coaxial cable comprising a center conductor (11), an insulator (12) provided on an outer periphery of the center conductor (11), an external conductor (13, 14) provided on an outer periphery of the insulator (12), and an outer coated body (15, 16) covering the external conductor (13, 14). The external conductor (13, 14) is constituted by a lateral winding shield (13) provided with metal fine wires laterally wound on the outer periphery of the insulator (12), and a metal resin tape (14) wound in a layer on the lateral winding shield (13) with a metal layer side being on an inside. The outer coated body (15, 16) is constituted by a resin tape (15) wound on the metal resin tape (14), and an extruded sheath (16) covering the resin tape (15). Given T1 as a thickness of the metal resin tape (14) and T2 as a thickness of the resin tape (15), T2/T1 is within a range from 0.180 to 0.800.

A transmission cable may include a conductor core, an insulator layer surrounding the conductor core, and a shielding layer surrounding the insulator layer, wherein the shielding layer includes a carbon nanotube sheet material.

A differential transmission cable includes a pair of signal lines, an insulation covering the pair of signal lines, and a shielding tape helically wound around the insulation. The shielding tape includes a conductor and an insulation layer that is formed on one surface of the conductor and that has a thickness of not less than 10 nm and less than 1 m.

A multi-core cable includes at least two coaxial wire pairs, each of the coaxial wire pairs including two coaxial wires being arranged side by side in contact with each other, each of the coaxial wires including a center conductor, an insulator, an outer conductor and a jacket, the outer conductor including an inner layer portion formed by thin metal wires being helically wrapped, and an outer layer portion formed by a metal resin tape being helically wrapped around the inner layer portion. A wrapping direction of the thin metal wires of the inner layer portion is opposite to a wrapping direction of the metal resin tape of the outer layer portion. An angle in the wrapping direction of the metal resin tape with respect to the wrapping direction of the thin metal wires is in a range of 30 or more but 90 or less. A cross-talk between the coaxial wire pairs is equal to or less than 40 dB.

A transmission cable may include a conductor core, an insulator layer surrounding the conductor core, and a shielding layer surrounding the insulator layer, wherein the shielding layer includes a carbon nanotube sheet material.

A shielded cable includes signal wires each having a signal conductor covered by an insulator, and a shield conductor comprising a metal foil resin tape spirally and overlappingly wrapped around the two signal wires, wherein an edge portion of the metal foil resin tape is folded back so that the metal foil therein is oriented outward, thereby bringing metal foils, which are arranged on lower and upper sides in the overlapping part of wrapping of the metal foil resin tape, into electrical contact with each other. The shielded cable includes two drain wires provided outside the metal foil resin tape and configured to be in electrical contact with an exposed part of the outwardly folded-back metal foil, which is exposed out of the overlapping part.

A differential signal transmission cable includes an insulated wire section including a pair of signal line conductors extending parallel to each other for transmitting a differential signal and an insulation covering the pair of signal line conductors, and a shield conductor including a band-shaped metal foil and spirally wound around the insulate wire section so as to overlap at a portion in a width direction thereof. An allowable elongation of the shield conductor as a stretchable limit in a longitudinal direction without breaking is not less than 2% at normal temperature.

A cable comprising hybrid carbon nanotube (CNT) shielding includes at least one conducting wire; at least one insulating layer covering at least one of the at least one conducting wire; a metallic foil component configured for lower frequency shielding function; and a CNT tape component configured for higher frequency shielding function.

A differential transmission cable includes a pair of signal lines, an insulation covering the pair of signal lines, and a shielding tape helically wound around the insulation. The shielding tape includes a conductor and an insulation layer that is formed on one surface of the conductor and that has a thickness of not less than 10 nm and less than 1 m.