Steady state analysis methods include time-domain shooting, multi-tone frequency-domain harmonic balance, multi-tone mixed-frequency-time methods. A similar set exists for envelope analysis, and for noise analysis.
Have a look at:
Mayaram, K. Lee, D.C. Moinian, S. Rich, D.A. Roychowdhury, J.
"Computer-aided circuit analysis tools for RFIC simulation:algorithms, features, and limitations",
IEEE Transactions on Circuits and Systems II, Volume 47, No 4, Apr 2000, Page(s): 274-286
http://laoo.dtc.umn.edu/~jr/research/PDFs/2000-TCAS2-Mayaram-Lee-Moinian-Rich-Ro...and Ken Kundert's "Introduction to RF Simulation and its Application,"
http://www.designers-guide.org/Analysis/rf-sim.pdf