For a new project I need to connect two boards via PCI express. For space reasons a custom cable assembly would be the best solution. But I'm not sure what is the best way to go here.
- I've seen Riser-Cards with simple ribbon-cables. But when I think about differential impedances etc. these solutions do not seem to be very promising.
- I've thought about a 2-layer Flex-PCB with a solid ground-plane. With some calculations I should be able to have the proper impedances for the high speed signals.
Is there any suggested way to handle this?