How do you solve the RF link issue between PCBs?

how do you solve the RF link between PCBs?
I have 1 PCB (first floor) and 2 PCB (second floor) distance about 15mm and need this PCB conect RF line (1GHz) 50Ohm.
How?

Use suitable board-to-board connectors...

It occurred to me
Question is, what connector is suitable for conducting RF analog signal?
preferably conector with defined impedance (50ohm).

You definitely need a controlled impedance board-to-board connector. You can see for instance:

Amphenol http://www.amphenolrf.com/products/a...2080056BD617F&
Huber-Suhner http://ipaper.ipapercms.dk/HUBERSUHN.../BoardtoBoard/
Tyco http://www.te.com/catalog/bin/TE.Con...81&M=FEAT&I=13

If possible, you can put on a SMA connector on each board and connect with a long SMA cable. You will have some losses though.

Try SMP connectors.