10 ghz lo
Hi Vfone,
Question is how good frequency stability you need at 10GHz.
Nowadays it is relatively chip to by LNBs for satellite tv reception (I think of the "heads" put into the focal point of outdoor parabolic dishes), especially if you look for old or second hand (maybe lightning-broken) ones. You can use the 10GHz DRO part of these LNBs I think with good results or can design some kind of AFC circuit around it if the stability of the LNB oscillator is not enough in itself.
This is just an idea to obtain cheap 10GHz components and adjust them to one's needs.
Regarding your frequency multiplier solution, it can be made less noisy if you start with some hundred MHz oscillator (the higher, the better) in which you use SAW resonator instead of crystal. SAW resonators are fabricated for several applications like remote controllers for car-door openers around 300MHz or 430MHz etc.
This way you may trade for less number of multiplier stages, especially, if you couple out the signal with a grounded-base bipolar transistor directly from the SAW resonator.
I mean if originally one of the resonator's leg was connected to ground in an oscillator, you lift that leg up with the very low input impedance of a grounded-base linear amplifier stage to couple out the signal from the oscillator. This way you use the resonator (this can be a crystal as well) as a narrow-band band-pass filter and this in itself reduces side-band noise/harmonics. Of course the resulting loaded-Q of the resonator suffers a little but you gain a "free" narrow band-pass filter! (This idea is not original from me but I mention it as a very good idea to filter oscillator side-band noise)
Regards, unkarc