Ah, I got the wrong end of the stick, I thought you were trying to make a VHF/UHF SDR do HF, not microwave...
What are your performance goals?
For a fixed 2GHz LO, a low phase noise crystal osc and multiply it is entirely conventional (And generally quieter then a YIG or such).
Look at something like a 'Driscoll' oscillator followed by the usual cascade of tuned multiplier stages, MMICs are your friends for getting the level back between stages. A PLL and VCO module looks attractive, but usually has horrible noise performance up there.
A conventional diode ring mixer will work, providing you can produce sufficient LO power (at least 50mW or so), but there are also printed structures with carefully placed diodes that you see in the microwave literature.
73 M0HCN