S-parameter black box model for ADS simulation

Can we use s-parameter black box model for HEMT device for all frequency and bias conditions for ADS microwave circuit simulation? Will it work in the nonlinear region too?

S-parameters are by definition linear small-signal parameters.
You will need different S-parameter sets for different bias conditions, and they will be valid for small signal only, at that given bias point.

S-parameters can be used in the linear regime and X-parameters in ADS used for the non-linear regime.

S parameter is got with fixed DC bias.If you want to simulate the DC,you have to get the nolinear model.

Does it mean I have to use x-parameters to do device modeling for non-linear regime?

Yes, X-parameters are a mathematical superset of S-parameters and are used for characterizing the amplitudes and relative phase of harmonics generated by nonlinear components under large input power levels.
for more information:
http://www.home.agilent.com/agilent/...0&lc=eng&cc=IR

Yes, X-parameters are a mathematical superset of S-parameters and are used for characterizing the amplitudes and relative phase of harmonics generated by nonlinear components under large input power levels.
for more information:
http://www.home.agilent.com/agilent/...0&lc=eng&cc=IR