Semi-suspended coplanar waveguide on a printed circuit board
View Patent ↗A printed circuit board includes two differential signal traces, a layer of core material, a layer of filler material, and a ground plane. The filler material is replaced by an air core under the differential signal traces.
1. A method of forming a coplanar waveguide having an air core comprising:
providing a layer of filler material over a conductive layer, the layer of filler material comprising at least one prepreg layer and at least one core material layer;
providing a channel in the layer of filler material;
providing a core layer over the channel and over remaining portions of the layer of filler material; and
providing two differential signal traces over the channel and over the core layer, wherein said coplanar waveguide is configured for 50 ohms impedance.
2. The method of claim 1 , wherein providing the channel includes drilling the channel in the layer of filler material.
3. The method of claim 1 , further comprising bonding the two differential signal traces to the core layer using an epoxy.
4. The method of claim 1 , further comprising bonding the layer of filler material to the conductive layer using an epoxy.
5. The method of claim 1 , further comprising bonding the at least one prepreg layer to the at least one core material layer using an epoxy.
6. The method of claim 1 , wherein providing the two differential signal traces includes etching the differential signal traces using photomasking.
7. A coplanar waveguide comprising:
a layer of core material having a first side and a second side, wherein the first side and the second side are on opposing sides of the layer of core material;
two differential signal traces disposed on the first side of the layer of core material;
a layer of filler material disposed on the second side of the layer of core material, wherein the layer of filler material comprises at least one prepreg layer and at least one core material layer;
a ground plane disposed on the layer of filler material, wherein the layer of core material and the ground plane are on opposing sides of the layer of filler material; and
an air core within the layer of filler material, wherein said coplanar waveguide is configured for 50 ohms impedance.
8. The coplanar waveguide of claim 7 , wherein the two differential signal traces comprise aluminum.
9. The coplanar waveguide of claim 7 , wherein the layer of filler material further comprises a plurality of alternating layers of prepreg material and core material.
10. The coplanar waveguide of claim 9 , wherein the layer of core material comprises FR4.
11. The coplanar waveguide of claim 9 , wherein the prepreg material comprises fiberglass.
12. The coplanar waveguide of claim 7 , wherein the air core is proximate to the two differential signal traces.
13. The coplanar waveguide of claim 7 , wherein the ground plane comprises copper.
14. The coplanar waveguide of claim 7 , wherein the two differential signal traces comprise gold plated copper.
15. The coplanar waveguide of claim 7 , wherein the two differential signal traces comprise copper.
16. A coplanar waveguide comprising:
a layer of core material having a first side and a second side, wherein the first side and the second side are on opposing sides of the layer of core material;
two differential signal traces disposed on the first side of the layer of core material;
two ground traces disposed on the first side of the layer of core material;
a layer of filler material disposed on the second side of the layer of core material, wherein the layer of filler material comprises at least one prepreg layer and at least one core material layer;
a ground plane disposed on the layer of filler material, wherein the layer of core material and the ground plane are on opposing sides of the layer of filler material; and
an air core within the layer of filler material, wherein said coplanar waveguide is configured for 50 ohms impedance.
17. The coplanar waveguide of claim 16 , wherein the two differential signal traces comprise aluminum.
18. The coplanar waveguide of claim 16 , wherein the layer of filler material further comprises a plurality of alternating layers of prepreg material and core material.
19. The coplanar waveguide of claim 18 , wherein the layer of core material comprises FR4.
20. The coplanar waveguide of claim 18 , wherein the prepreg material comprises fiberglass.
21. The coplanar waveguide of claim 16 , wherein the air core is proximate to the two differential signal traces.
22. The coplanar waveguide of claim 21 , wherein the two differential signal traces are between the two ground traces.
23. The coplanar waveguide of claim 16 , wherein the ground plane comprises copper.
24. The coplanar waveguide of claim 16 , wherein the two differential signal traces comprise gold plated copper.
25. The coplanar waveguide of claim 16 , wherein the two differential signal traces comprise copper.
26. A method of forming a coplanar waveguide having an air core comprising:
providing a layer of filler material over a conductive layer, the layer of filler material comprising at least one prepreg layer and at least one core material layer;
providing a channel in the layer of filler material;
providing a core layer over the channel and over remaining portions of the layer of filler material; and
providing two differential signal traces and two ground traces over the core layer, wherein said coplanar waveguide is configured for 50 ohms impedance.
27. The method of claim 26 , wherein the step of providing the layer of filler material includes using a plurality of alternating layers of prepreg material and core material.
28. The method of claim 26 , wherein the two differential signal traces are provided over the channel.
29. The method of claim 28 , wherein the two differential signal traces are provided between the two ground traces.