1. A printed circuit board (PCB) comprising:a first insulating layer;
a pad disposed on the first insulating layer;
a first reference layer on which the first insulating layer is disposed, the first reference layer comprising:
a dielectric passage disposed through the first reference layer, and for forming a return path of a signal that is transmitted to the pad; and
a conductive line disposed in and through the dielectric passage, and for forming a transmission path of the signal;
a second insulating layer on which the first reference layer is disposed; and
a second reference layer on which the second insulating layer is disposed, the second reference layer further forming the return path,
wherein a capacitance of the pad corresponds to a distance between the pad and the second reference layer.