Or get even further back to basics and MAKE a directional coupler.
It's not all that difficult, and not bad to check for directionality.
RFSim99 has a tool for designing microstrip and other couplers (though
it fails to tell you that for the given coupling, the microstrip lines
should be coupled for a quarter wave distance). Hint: people who
manufacture equipment that operates in the GHz region often put
couplers right on the PC boards--biggest cost is a bit of real estate.

Cheers,
Tom