Do a search on the EDA Board some time ago I recall someone posting such a schematic,however it was never said if this circuit actually worked,but it may be worth a search.
I think it doesn't matter because what the circuit is doing is transmitting noise allover the gsm band so it doesn't matter what is the company or where it is
The question now is how can I design the vco (I don't know how to design or print the microstrip, in fact I don't know what the microstrip really is) ,I hope someone could really help me.