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Im a bit on the bad side with hittite right now, when i was working at the big M i didnt have any problems getting samples from them but now its not as easy , they want me to buy the samples but then they have a min order of 10ea which really is overkill financially !
The reason why you cant get past 10GHz is that as far as i know those YIGs use bipolar transistors and not GaAS, the phase noise performance seem to support this theory, getting anything out of a bipolar transistor past 10GHz is a tough job, i spend countless days and month testing simulating and building prototypes trying to get a 12GHz DRO going (to be used as one half of a push push design for 24GHz), there are a few good devices from infineon and a fairly new one from NXP that produce results but back when those endwave parts were conceived state of the art was about 10GHz !
Im really only interested in 8GHz which the device should do, im using a passive doubler to go to 16GHz and then a MIMIX Doubler to go to 32GHz, why a passive doubler for the first stage ? well the answer is simple, im getting about +14dBm from the YIG, active doublers usually take about -6 to 0dBm so i would have to kill almost 14dB, the conversion loss of the doubler is 12dB so im ending up with +2dBm, now run this signal trough a splitter, lose 6dB thats -4dBm , the active doubler i use produces +16dBm @ 0dBm input so im getting about +14dBm at the output which is perfect.


John Miles <jmiles@...> wrote:
I have tried running those YTOs past 10 GHz, and what happens is that they
just stop oscillating beyond a certain point (about 10.3 GHz as I recall).
If you bolt the oscillator to a good thermal sink and keep an eye on the
temperature it will probably be safe enough... but whether it will still
oscillate is another question.

I'd be interested in hearing how things go with the sampling phase detector.
Conversion loss at high harmonics, and the resulting need for lots of IF
gain, can really eat your lunch with those. From what I've seen there is no
longer much upside to using harmonic samplers over modern PFD chips. The
best of the Analog Devices parts (ADF4108, about $7/ea.) will work at Fin=8
GHz and Fcomp=100 MHz. You can't run either of them at N=32,000 and expect
miracles, obviously.

Obligatory HP content: I spent a lot of time trying to clean up my 8566B's
first LO synthesizer before I realized that the conversion loss of the YTO
sampler was never going to let me do better than about -105 to -110 dBc/Hz.
The low effective N factor rules out the ADF41xx series PLLs in that
application, but I think I could have gotten into the -120 dBc/Hz range with
a Hittite HMC363/HMC439 combination if my motivation hadn't run out.

-- john, KE5FX