is spectre rf similator to advanced design system
I use both tools, as standalone and with RFDE.
ADS is frequency basad simulator with a lot of stuffs to simulate complex signals
SpectreRF is the RF IC design standard and is a time based simulator.
In my opinion the two tools are complementary in some sense (and that's why Agilent and Cadence are working together into the RFDE integration).
In my experience (RF IC designs) I have seen that in general the accuracy of the simulators can be quite similar, but with different practical aspects:
-for small signal analysis (ac, noise) without frequency conversion and transients I prefer spectre, is really more and more user friendly.
-for linearity simulations on amplifiers (IIP1,IIP3) ADS is really superior in term of efficiency. This is also true if you're simulating circuits with largely spaced harmonics (such as direct conversion mixers, for example)
-for mixers with RF/IF ratio of about 10/15 the two simulators are comparable, so I prefer spectre (not for IIP3).
I hope it can help.
Bye
Mazz