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:
forming 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;
forming a channel in the filler material;
forming a core layer over the channel and over remaining portions of the filler material; and
forming two differential signal traces over the channel and over the core layer.
2. The method of claim 1 , further comprising bonding the two differential signal traces to the core layer using an epoxy.
3. The method of claim 1 , further comprising bonding the layer of filler material to the conductive layer using an epoxy.
4. 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.
5. The method of claim 1 , further comprising etching the differential signal traces using photomasking.
6. The method of claim 1 , further comprising drilling the channel in the filler material.
7. A coplanar waveguide comprising:
a layer of core material;
two differential signal traces on the layer of core material;
two ground traces on the layer of core material;
a layer of filler material below the layer of core material, the layer of filler material comprising at least one prepreg layer and at least one core material layer;
a ground plane; and
an air core under the layer of core material.
8. 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.
9. The coplanar waveguide of claim 8 , wherein the layer of core material comprises FR4.
10. The coplanar waveguide of claim 8 , wherein the prepreg material comprises fiberglass.
11. The coplanar waveguide of claim 7 , wherein the air core is under the two differential signal traces.
12. The coplanar waveguide of claim 11 , wherein the two differential signal traces are between the two ground traces.
13. The coplanar waveguide of claim 7 , wherein the ground plane compnses 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. The coplanar waveguide of claim 7 , wherein the two differential signal traces comprise aluminum.
17. A method of forming a coplanar waveguide having an air core comprising:
forming 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;
forming a channel in the filler material;
forming a core layer over the channel and over remaining portions of the filler material; and
forming two differential signal traces and two ground traces over the core layer.
18. The method of claim 17 , wherein the two differential signal traces are formed over the channel.
19. The method of claim 18 , wherein the two differential signal traces are formed between the two ground traces.
20. The method of claim 17 , wherein the layer of filler material further comprises-a plurality of alternating layers of prepreg material and core material.