7 110 263

7,110,263 Title:

Reference slots for signal traces

An apparatus comprises a signal layer including a first and second signal trace. The apparatus also comprises a first reference plane including a first slot substantially parallel to the first and second signal traces. Further, the apparatus includes a dielectric layer having at least a portion disposed between the signal layer and the first reference plane.

What is claimed is:

1. An apparatus comprising: a signal layer including a first and a second signal trace located along a first plane, each of the first and second signal traces comprises afirst segment with a first segment width, and a second segment with a second segment width; a reference layer located along a second plane that is substantially parallel with the first plane coupled to the first and the second signal trace, thereference layer includes a slot substantially parallel to the first and second signal traces, the slot comprising a first portion and a second portion having a first portion width and a second portion width, respectively; and wherein the first andsecond portions of the slot correspond to the first and second segments, respectively, of the first and second signal traces.

2. The apparatus of claim 1, further comprising a dielectric layer that is at least partially disposed between the signal layer and the reference layer.

3. The apparatus of claim 1 wherein spacing between the first and the second signal trace remains substantially constant in both the first and second segments.

4. The apparatus of claim 1 wherein each of the first and second signal traces further comprises a third segment with a third segment width and the slot comprises a third portion, comprising a third portion width, corresponding to the thirdsegment of the first and second signal traces.

5. The apparatus of claim 1 wherein the first and second signal traces have a first and a second signal trace width respectively, wherein the first signal trace width is substantially the same as the second signal trace width.

6. The apparatus of claim 1 wherein the signal layer further includes a third and a fourth pair of signal traces and another slot.

7. The apparatus of claim 2 further comprising: another reference layer located along a third plane that is substantially parallel with the first plane, coupled to the first and the second signal trace, the other reference layer includinganother slot substantially parallel to the first and second signal traces; and the dielectric layer is further partially disposed between the signal layer and the other reference layer.

8. An assembly comprising: an apparatus comprising: a signal layer including a first and second signal trace located alone a first plane, each of the first and second signal traces comprises a first segment with a first segment width, and asecond segment with a second segment width; a reference layer located along a second plane that is substantially parallel with the first plane coupled to the first and the second signal trace, the reference layer includes a slot substantially parallelto the first and second signal traces, the slot comprising a first portion and a second portion having a first portion width and a second portion width, respectively; and wherein the first and second portions of the slot correspond to the first andsecond segments, respectively, of the first and second signal traces, a processor coupled to the apparatus; and a networking interface coupled to the apparatus.

9. The assembly of claim 8 wherein the first and second signal traces are coupled to the processor and a memory device.

10. The assembly of claim 8, further comprising a dielectric layer that is at least partially disposed between the signal layer and the reference layer.

11. The assembly of claim 8 wherein spacing between the first and the second signal trace remains substantially constant in both the first and second segments.

12. The assembly of claim 10 further comprising: another reference layer located along a third plane that is substantially parallel with the first plane, coupled to the first and the second signal trace, the other reference layer includinganother slot substantially parallel to the first and second signal traces; and the dielectric layer is further partially disposed between the signal layer and the other reference layer.

13. The assembly of claim 8 wherein the first and second signal trace are to facilitate propagation of a differential signal pair.

14. A system comprising: an assembly comprising: an apparatus comprising: a signal layer including a first and second signal trace; located along a first plane, each of the first and second signal traces comprises a first segment with a firstsegment width, and a second segment with a second segment width; a reference layer located along a second plane that is substantially parallel with the first plane coupled to the first and the second signal trace, the reference layer includes a slotsubstantially parallel to the first and second signal traces, the slot comprising a first portion and a second portion having a first portion width and a second portion width, respectively; and wherein the first and second portions of the slotcorrespond to the first and second segments, respectively, of the first and second signal traces and a processor coupled to the apparatus; and a networking device coupled to the assembly.

15. The system of claim 14 wherein the a assembly further comprises a networking interface, wherein the networking interface is coupled to the networking device.

16. The system of claim 14 wherein the assembly further comprises an interface to a persistent storage and wherein the system further comprises the persistent storage coupled to the interface to the persistent storage.

17. A method of routing circuit board traces comprising: routing a first signal trace and a second signal trace along a first plane of a circuit board, each of the first and second signal traces comprises a first segment with a first segmentwidth, and a second segment with a second segment width; and routing a slot in a reference layer located along a second plane of the circuit board that is substantially parallel with the first plane coupled to the first and the second signal trace, theslot is substantially parallel to the first and the second signal traces the slot comprising a first portion and a second portion having a first portion width and a second portion width, respectively and wherein the first and second portions of the slotcorrespond to the first and second segments, respectively, of the first and second signal traces.