Patent ID: 8143526
Filing Date: 2012-03-27
Classification: H05K

Abstract:
1. A flexible printed circuit board (FPCB) comprising: a signal layer, wherein a differential pair comprising two transmission lines is arranged in the signal layer, and two first sheets made of a conductive material are arranged at opposite sides of the differential pair in the signal layer symmetrically, the two first sheets are parallel to the two transmission lines, and are coupled to ground; a ground layer, wherein two second sheets made of a conductive material are arranged in the ground layer; the two second sheets are at a distance from each other to form a void in the ground layer opposite to the differential pair; and an insulating layer made of a dielectric material and arranged between the signal layer and the ground layer; wherein the differential pair comprises a plurality of section pairs, each of the plurality of section pairs comprises two sections arranged in the two transmission lines symmetrically, every two adjacent sections of each of the two transmission lines are different in width, each of the plurality of section pairs has a desired characteristic impedance relative to a predetermined distance between each of the two sections of each of the plurality of section pairs and a corresponding nearest first sheet, and a predetermined distance between the two sections of each of the plurality of section pairs.