| Designing PCB's at GHz - Click HERE for Original Thread |
| eeka chu |
I got bored and went googling when I found some pictures of PCBs designed for GHz signals.
I knew before I saw the pictures roughly the amount of voodoo design effort it takes to produce these, but some of the boards looked literally as if they'd been pulled from a UFO. The traces had crop circle and aztec writing style elements to them. 'Random' traces start and stop and seem to connect to nothing, or curve around and come to a dead end, or fan out in a cone shape with nothing on them.
Does anyone know any good books that cover what the superstar jive powered funk is going on with these things? They're just unbelievable. :xeye: |
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| pinkmouse |
| I was recommended this one, but I didn't have the money to purchase at the time. |
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| I_Forgot |
All those shapes are about controlling impedances. If you put a short at the end of a 1/4 wavelength stub, the other end of the stub looks like infinite Z, for example.
Those boards are usually some expensive materials- ordinary G7 isn't manufactured under tight enough tolerances to get controlled impedance lines. Teflon and other high dielectric constant materials are used to keep tolerances tight and line widths narrow, and to minimize thickness of the substrate (this minimizes ground inductance).
I have a couple books in boxes somewhere from back when I used to design RFICs... let me see if I can find them and get the titles..
I_F |
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