Patent ID: 8101863

Claim:
A flexible printed circuit board comprising: a base insulating layer having a first surface and a second surface, the base insulating layer having a dielectric constant of not less than 3.2 and not more than 4.0; a plurality of conductor patterns formed on the first surface of said base insulating layer; a protective layer formed on the first surface of said base insulating layer so as to cover said plurality of conductor patterns, the protective layer having a dielectric constant of not less than 3.2 and not more than 4.0; a ground layer formed on the second surface of said base insulating layer opposite to said protective layer; and a high dielectric insulating layer formed on said protective layer and having a dielectric constant of not less than 10 nor more than 30, wherein said high dielectric insulating layer is formed on said protective layer and not on said ground layer.