A transmission wiring structure, associated design structure and associated method for forming the same. A structure is disclosed having: a plurality of wiring levels formed on a semiconductor substrate; a pair of adjacent first and second signal lines located in the wiring levels, wherein the first signal line comprises a first portion formed on a first wiring level and a second portion formed on a second wiring level; a primary dielectric structure having a first dielectric constant located between the first portion and a ground shield; and a secondary dielectric structure having a second dielectric constant different than the first dielectric constant, the secondary dielectric structure located between the second portion and the ground shield, and the second dielectric layer extending co-planar with the second portion and having a length that is substantially the same as the second portion.