Printed circuit board

1. 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.

2. The PCB of claim 1 , wherein the two capacitors are surface mount DC block capacitors, the second and the third conductive layers are layers of the electrical ground level with respect to the high-speed transmission line portions.

3. The PCB of claim 1 , wherein the first conducting layer further comprises two additional soldering pads being disposed at an end of the first high-speed transmission line portion, and configured to physically and electrically connect the first high-speed transmission line portion and the capacitors.

4. The PCB of claim 1 , wherein the soldering pads in the first conductive layer and the connecting portions in the fourth conductive layer are respectively merged into end portions of the through-hole vias, the end portions of the through-hole vias being circular pads.

5. A printed circuit board comprising: a first conductive layer comprising a first high-speed transmission line portion and two soldering pads;

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 and a second high-speed transmission line portion directly connected to the two connecting portions;

two through-hole 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;

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; and

wherein the first and the second high-speed transmission line portions are differential pair type of microstrip lines.

6. The PCB of claim 5 further comprising at least two ground vias respectively disposed across the second insulating layer and electrically connected with the second conductive layer and the third conductive layer and not extending beyond the second conductive layer and the third conductive layer.

7. The PCB of claim 6 , wherein the first conductive layer further comprises at least two first stubs, the fourth conductive layer further comprises at least two second stubs, the at least two ground vias are respectively disposed across the first insulating layer, the second conductive layer, the third conductive layer, and the third insulating layer, and electrically connected with the at least two first stubs and the at least two second stubs.

8. The PCB of claim 5 , wherein the first and the second high-speed transmission line portions are coplanar waveguides, respectively comprising a top surface ground plane and a bottom surface ground plane.

9. The PCB of claim 8 further comprising at least 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 electrically connected with the top surface ground plane, the bottom surface ground plane, the second conductive layer, and the third conductive layer.

10. The PCB of claim 5 , wherein the two capacitors are surface mount DC block capacitors, the second and the third conductive layers are layers of the electrical ground level with respect to the high-speed transmission line portions.

11. The PCB of claim 5 , wherein the soldering pads in the first conductive layer and the connecting portions in the fourth conductive layer are respectively merged into end portions of the through-hole vias, the end portions of the through-hole vias being circular pads.

12. The PCB of claim 5 , 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.

13. A printed circuit board comprising:

a first conductive layer comprising a first high-speed transmission line portion and two soldering pads;

a first insulating layer disposed under the first conductive layer;

a fourth conductive layer disposed under the first insulating layer and comprising a second high-speed transmission line portion;

two through-hole vias respectively disposed across the first 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 second high-speed transmission line portion respectively;

wherein the first and the second high-speed transmission line portions are differential pair type of microstrip lines; and

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 layer is about 0.1 mm or less respectively.

14. The PCB of claim 13 , further comprising 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; and a third insulating layer disposed under the third conductive layer, wherein 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 electrically isolated from the second conductive layer and the third conductive layer.

15. The PCB of claim 14 , wherein the window in the second conductive layer extends to an area under the two soldering pads in the first conductive layer.

16. The PCB of claim 13 , wherein the first and the second high-speed transmission line portions are coplanar waveguides, respectively comprising a top surface ground plane and a bottom surface ground plane.

17. The PCB of claim 16 further comprising at least two ground vias respectively disposed across the first insulating layer, and electrically connected with the top surface ground plane and the bottom surface ground plane.

18. The PCB of claim 13 , wherein the soldering pads in the first conductive layer and the second high-speed transmission line portion in the fourth conductive layer are respectively merged into end portions of the through-hole vias, the end portions of the through-hole vias being circular pads.