jtos 3000 vco
Commercially available crystal resonators on 550 MHz you can not find but you can try one of following solutions. First is what I would do:
0. You can use one of hundreds PLL ICs available in that frequence range and follow the application note. Use a VCO like JTOS 3000 from mini-cicuits or similar from Z-comm.
1. I understood that you want just to generate one channel at 2.2 GHz and you do not need another frequencies. I suppose that you have just prescaler dividing by 4 and therefore you would like to have so high reference. If jou do not have extreme phase noise demands use a prescaler dividing by 64 (e.g. UPB 1507 ftom NEC) allowing you to get a crystal on 34.375 MHz and that you can buy easy. Second advantage is that you can use digital phase comparators instead of mixer that you must use for 550 MHz reference.
2. You can use 180 MHz 7th overtone crystal oscilator and use its 3d harmonic as reference for your loop. Drawbacks: you need filtering and amplifying for the harmonic and you must build the oscillator from discrete components. Of course it will also cost more. You can even try to use 11th or 13th harmonic of a crystal oscillator without a loop.
3. If frequency stability is not a very big issue for you, you can try to use SAW resonator oscillator as a reference.
Actually, the possibilities for generating a 2.2 Ghz signals are unlimited, maybe it is best for you to specify your problem exactly and the solition could be readily found.
Regards,
D