Geronimo said:
I think transmitting high-speed signals is very easy when you have a
360-degree ground reference, round conductors,
and no other nearby signals like in coaxial cables. My aim is to design PCB
tracks as much like a coaxial cable as
possible. Anyone tried this before? Is it possible with regular FR4, anyway?
Thanks for your help.
Gero
I would think that would be difficult and/or costly.
Working from bottom to top:
Start with (say) 6 mil laminate 0.5/0.5 at bottom; bottom layer has a
narrow stripe to emulate the lowest part of a coax, and top part is a
wider stripe: both ground (shield).
Next layer (#2) is (say) 6 mil laminate 0/0.5 (ie bottom has no
copper and top is 0.5 ounce); stripe is wider and is ground.
"Middle" or next layer is (say) 6 mil laminate 0/0.5 (ie bottom has
no copper and top is 0.5 ounce); 3 stripes: ground / center conductor /
ground.
Next layer is (say) 6 mil laminate 0/0.5 (ie bottom has no copper and
top is 0.5 ounce); stripe is as wide as layer #2.
Then use (say) 6 mil laminate 0/0.5 at top; where the top copper has
a "wide" stripe same as first laminate top stripe as ground.
Finish with (say) 6 mil laminate 0/0.5 at top; where the top copper
has a "narrow" stripe same as first laminate bottom stripe as ground.
Use more layers if they are thinner.
Use vias liberally for tying the ground stripes together.
Note the 6 mils is a wild guess.