Plotting IMD3 Terms in Polar Form on Cadence

Hi all,

I am referencing this paper:

Modified Derivative Superposition, Aparin and Larson
http://course.ee.ust.hk/elec528/Note...-%20Larson.pdf


I am having trouble getting a plot like in Figure 7 where it displays the IMD3 components.

I can determine the ordered nonlinearity terms from (3) easily using a dc sweep of Vgs and taking the deriative. But how would I only display this at a certain Vgs? For example I have the calculator function deriv(deriv(deriv(Id)))/6 but what If I want it at a certain Vgs like Vgs=0.5?

Assuming I can do this, can I also do a ac analysis at the same time? If so, I could get vgs from probing vg and vs and get vgs^3. This will have a phase component with it so ideally I could put g3*vgs^3 in vector form but how would I do this?

Thanks,

William