The present invention relates to a high speed transmission cable (100A) that includes a first conductor set (110), a dielectric film (120A) at least partially concentrically disposed around the first conductor set (110) and a pinched portion (150A) forming an insulating envelope (140A) around the first conductor set (110). The dielectric film (120A) includes a base layer (122) having a plurality of first protrusions (124) formed on a first major surface of the base layer (122), wherein the dielectric film (120A) is disposed such that the base layer (122) is partially concentric with the conductor set (110) and wherein a portion of the first protrusions (124) is disposed between the first conductor set (110) and the base layer (122) in a region where the base layer (122) is concentric with the first conductor set (110).