Are there any special internal Ethernet connectors other than RJ45?

I am working on the board that suppose to have 1 GbE port (10/100/1000BASE-T). Looking at connectors all I seem to find is standard RJ45 connector.

However in my design the board itself is not directly exposed to the outside, there is a backplane which will include some other ports as well.

Now, I could put the standard RJ45 on the board and and 2 of them on backplane and connect board to backplane with standard CAT5 cable. However the RJ45 connector is rather bulky comparing to everything else on board.

So my question is -- are there any alternatives to this approach, how do commercial products that do not expose main board ports directly work around that?

PS: I've seen this question which recommends micro USB 2.0 port as chip alternative, but that means only 4 wires per port (so 2 ports per board for single RJ45?) I foresee some impedance matching issues right there.

Answer

You need to use a different ethernet standard than 802.3ab, that doesn't need RJ45 jacks. Like IEEE 802.3ap “Backplane Ethernet”, which supports gigabit speeds over a backplane type of connection. This standard was designed for your application in mind.

Also see On-Board connection of ethernet transceivers for 10/100 speed connections on the same board. The Micrel now Microchip app note AN-120 http://ww1.microchip.com/downloads/en/AppNotes/Capacitive%20Coupling%20Ethernet%20Transceivers%20without%20Using%20Transformers.pdf describes how non-transformer (and connector) ethernet connections are designed on board.