Printed circuit board

1. A printed circuit board comprising:

a ground layer;

a power source layer that is provided to be opposed to the ground layer;

a signal wiring layer that transmits a signal in a predetermined frequency domain;

an insulating layer that insulates the ground layer, the power source layer and the signal wiring layer from one another; and

an electromagnetic radiation suppressing member that is provided to cover a circumferential edge of the insulating layer and that has a negative dielectric constant and a positive magnetic permeability in a frequency domain including the predetermined frequency domain,

wherein the electromagnetic radiation suppressing member includes a thin film layer in which nanosized particles of metal or semiconductor are dispersed in a given density,

wherein the electromagnetic radiation suppressing member includes an insulating sheet to which the thin film layer is bonded.

2. The printed circuit board according to claim 1 , wherein the particles are of an alloy or a eutectoid made from at least one selected from the group consisting of Fe, Al, Ni, Ag, Mg, Cu, Si and C.

3. The printed circuit board according to claim 1 , wherein the electromagnetic radiation suppressing member entirely covers both of side surfaces of the power source layer and side surfaces of the ground layer.

4. The printed circuit board according to claim 3 , wherein the electromagnetic radiation suppressing member has a U-shape.