using Agilent ADS......

Is there a way out in Agilent ADS where i can plot ft(unity current gain freq) or fmax(unity power gain freq) against variables like Gate voltage, Gate width etc.....

This will help to find FT versus Bias ( I have used BJT in my case but you can change )
For fmax, the approximated fmax equation would help you but it's just an approximation and sometimes it may be very different than reality.

thnks for pointing out to cross().........but, if i want to plot fT against wf(width of gate of MOS), i should get 'wf' on the x axis.......but by default, the parameter being swept in the ac simulation controller comes on the x axis....is there a way to get the variable in the 'parameter sweep' to be on the x axis ?......for eg in your case which u showed me in the attached pdf above could we plot, FT against Ibias?............in other words, i want to sweep freq from 1 to 60GHz, i have a single value of parameter sweep variable 'wg' and i compute a single value of fT using the cross() for each entire frequency sweep of 1 to 60GHz......i want a plot of fT against 'wg'...............

Sure..
If you fix the other variables such as Vds,Vgs, etc. You may assign "Wg" being as variable ( like Ibias ) and you change this and you will obtain FT versus Wg.But in your case, Wg should able to be assigned as a variable ( some models don't allow that..)

i'm able to make 'wg' a variable, thts not an issue....but the problem is i'm unable to bring 'wg' on the x axis,since the sweep variable in the simulation controller comes on the x axis by default......if I make 'wg' the sweep variable in the AC simulation controller, how do i sweep the frequencies?.....