S-params can be result of nonlinear model of device, or it is used only ofr ac/dc?

[Terminator3]

In simulation packages, like ADS, MWO, HFSS, QUCS, SPICE,.... device can be represented with s-parameters or non-linear model. Does that mean that S-parameters not used in non-linear model, and are just result of all that transistor parameters and capacitance values?

 

[pancho_hideboo]

S-parameter is a linear model which is derived at specific DC operation point of nonlinear model.

 

[N.Narayanan]

S-parameter is the electrical characteristics of the particulater device whcich was modeled across frequecny (ac) and with dc (in case of transistor)

 

[AmirMohammad]

Hi, you can use s2p model or nonlinear model in simulation softwares. If you use s2p model, software uses fixed s2p parameters defining component in all conditions such as bias, etc. , but if nonlinear model is used then software applies biasing condition to the component and calculates s-parameters at those conditions and therefore with nonlinear model you can change biasing conditions while s-parameters are valid.

 

[FvM]

S-parameters are not necessarily the "result" of the non-linear model. At least when presented in a manufacturers datasheet, they are moreoften empirical measurement results while the non-linear model is a theoretical consruct that has been fitted to a set of measurements. Hopefully, it's results conform to the given S-parameters, but not necessarily exactly and rarely in all possible operation points.