A dual axial cable may include two substantially parallel and substantially adjacent wires, each wire formed from an electrical conductor surrounded throughout its length by a bifurcated electrical insulator. Each bifurcated electrical insulator may include a first portion of electrically insulative material and a second portion of electrically insulative material having a dielectric constant substantially higher than a dielectric constant of the first portion, such that a cross-section of each wire includes its respective first portion and respective second portion. The cable may be configured such that throughout the length of the cable, the second portions of each of the two wires are substantially adjacent to each other.