Patent ID: 8841976

Claim:
A printed wiring board comprising: a first insulating layer; a ground layer formed on one main surface of the first insulating layer; a signal line formed on other main surface of the first insulating layer; two conductive lines formed on the other main surface of the first insulating layer and juxtaposed to the signal line such that the signal line is interposed between the conductive lines; and a second insulating layer laminated at a side of the other main surface of the first insulating layer so as to cover the signal line and the conductive lines, wherein, upon a dielectric tangent of the second insulating layer being larger than a dielectric tangent of the first insulating layer, the printed wiring board is configured to have a relationship as follows: (a relative permittivity of the first insulating layer)·(a width of the signal line)/(a thickness of the first insulating layer)>(a relative permittivity of the second insulating layer)·((a thickness of the signal line)/(a distance between the signal line and one of the conductive lines)+(the thickness of the signal line)/(a distance between the signal line and the other of the conductive lines)).