Patent ID: 8748753

Claim:
A printed circuit board comprising: a first conductive layer comprising a first high-speed transmission line portion, two soldering pads, and two first stubs; a first insulating layer disposed under the first conductive layer; a second conductive layer disposed under the first insulating layer; a second insulating layer disposed under the second conductive layer; a third conductive layer disposed under the second insulating layer; a third insulating layer disposed under the third conductive layer; a fourth conductive layer disposed under the third insulating layer and comprising two connecting portions, two second stubs, and a second high-speed transmission line portion directly connected to the two connecting portions; two through-hole vias and two ground vias respectively disposed across the first insulating layer, the second conductive layer, the second insulating layer, the third conductive layer, and the third insulating layer; and two capacitors respectively connecting the first high-speed transmission line portion and the two soldering pads; wherein: the two through-hole vias are directly connected with the two soldering pads and extending the connection to the two connecting portions respectively; the two ground vias are physically and electrically connected with the two first stubs and the two second stubs, and electrically connected with the second conductive layer and the third conductive layer respectively; and two windows are respectively defined in the second conductive layer and the third conductive layer in the vicinity of where the through-hole vias pass through so that the through-hole vias are physically and electrically isolated from the second conductive layer and the third conductive layer; the window in the second conductive layer extends to an area under the two soldering pads in the first conductive layer; wherein the first and the second high-speed transmission line portions are differential pair type of microstrip lines; and wherein the edge-to-edge separation between the soldering pads in the first conductive layer is about 0.2 mm to about 0.3 mm, and the thickness of the first, the second, and the third insulating layers is about 0.1 mm or less respectively.