Printed circuit board and method of manufacturing the same

摘要

A differential transmission path composed of a pair of transmission lines is formed on an upper surface of a base insulating layer. A ground conductor layer is formed on a lower surface of the base insulating layer. The ground conductor layer is opposite to the differential transmission path with the base insulating layer sandwiched therebetween. A spacing between the transmission lines at a part of the differential transmission path is smaller than a spacing between the transmission lines at another part of the differential transmission path. A thickness of a part of the ground conductor layer overlapping the part of the differential transmission path is smaller than the thickness of another part of the ground conductor layer overlapping the another part of the differential transmission path.

主权项

1. A printed circuit board, comprising:
a first insulating layer; a differential transmission path composed of first and second transmission lines; and a ground conductor layer, wherein said ground conductor layer, said first insulating layer and said differential transmission path are stacked such that said ground conductor layer is opposite to said differential transmission path with said first insulating layer sandwiched therebetween, a spacing between said first and second transmission lines at one part of said differential transmission path is smaller than a spacing between said first and second transmission lines at another part of said differential transmission path, said ground conductor layer including first and second conductor layers, said first conductor layer being formed to overlap the one part and the other part of said differential transmission path, said second conductor layer being formed to overlap the other part of said differential transmission path and not to overlap the one part of said differential transmission path, said second conductor layer being stacked on said first conductor layer so as to come into contact with said first conductor layer, and a thickness of a part of said ground conductor layer overlapping said one part of said differential transmission path is smaller than a thickness of another part of said ground conductor layer overlapping the other part of said differential transmission path.