Abstract: An electrical transmission unit line is provided comprising a porous dielectric layer having positioned on one side thereof a pair of narrow, parallel elongated electrical conductors and on the other side thereof, opposite the pair of conductors and extending transversely across both wires of the pair and parallel thereto, a wide ground conductor. An electrical transmission line having a plurality of such unit lines is also provided. The porous dielectric is preferably porous, expanded polytetrafluoroethylene. The transmission lines are covered with an electrically insulating material, preferably a nonporous plastic.