A coaxial cable is a wire and signal transmission line. It is generally caused by four layers of material: the innermost is a conductive copper wire, and the outside of the wire has a layer of plastic (used as an insulator, a dielectric). On the outside of the insulator, there is a thin mesh of conductive bodies (usually copper or alloy). Then the conductor is outside the outermost layer of insulating material as the outer skin.
