Re: Modeling a new device
I would take a look at IC_CAP one Agilent's wewb site; they may have some tutorials on creating spice models like BSIM, EEFET, MOS1..etc. Also if you have s-parameters ADS will create a lumped element equivalent circuit. This is an open-ended question since it depends on whether it's an active or passive device, the frequency range of interest ..etc. I'm involved with developing models for high power transistors if you like you could pm me for proprietary concerns.
Regards,
MoonShine