Patent ID: 7372143

Claim:
A printed circuit board comprising: first, second and third insulating layers over laid on one another in this sequence; a via penetrating through the first, second and third insulating layers; a guard pattern made of an electrically-conductive material, said guard pattern extending on a front surface of the first insulating layer along a circle concentric with the via; and an electrically-conductive body extending from the guard pattern and penetrating through the first insulating layer along an imaginary cylinder concentric with the via; a ground pattern made of an electrically-conductive material, the ground pattern formed on a surface of the second insulating layer, said ground pattern receiving a tip end of the electronically-conductive body; and a cylindrical ground wall made of an electrically-conductive material, the cylindrical ground wall extending from the ground pattern along an imaginary cylinder concentric with the via, said cylindrical ground wall penetrating through at least the second insulating layer.