In my design I want to connect a PHY (88E1512) to a switch which contains another PHY (BCM53115M). The devices are separated by a few inches of PCB and will be impedance matched. Both have the same ground reference but different power supplies. Ethernet also seems to have a 1m distance requirement between ports.
I'm able to place magnetics in between the two but I wanted to know the logic behind requiring magnetics between two on board PHYs. I have also heard of using capacitive coupling instead of magnetics all together and was wondering for such short distances are magnetics better or would simply capacitive coupling be better like in this question: Connecting two Ethernet PHY without magnetics?
Note: Both devices seem to have termination inside them.