Patent 7781680 was granted and assigned to Hon Hai Precision Industry Co Ltd on August, 2010 by the United States Patent and Trademark Office.
An exemplary FPCB includes a differential pair consisting of a first transmission line and a second transmission line, a signal layer with the first transmission line arranged therein, a ground layer having a void which includes the area beneath the first transmission line, and a dielectric layer lying between the signal layer and the ground layer. The second transmission line is arranged in the ground layer offset from the first transmission line in the horizontal direction. The FPCB can transmit high speed signals.