HI, first I have checked the calculation above.
1
The shunt capacitor is miller capacitor in addition of Cds.
Definition of Cds is "capacitive current out of the drain due to a change in source voltage".
but source node is actually short to ground, so why add it?
2
I have proved that maximum voltage gain degrades because some current doesn't flow through M1.
C1=Csg+Cbg=8.75f, C2=Cdg-Covlgd=12.88f, L3=2.35n
Z1=-730.49j, Z2=-496.26j, Z3=367.7j
voltage division = 0.85 and closed to
maximum volatge gain drop expressed as 10.1/11.56=0.874
but notice that
1) I ignored some capacitors are negative(otherwise reactance of them should be positive), does that matter?
2) I didn't take Covlgs into account because I think source node is short to ground, is that right?
3) I also check output noise.
In simulation configuration, I choose outpout as voltage (drain node of M1 as positive and gnd as negative), and input as probe (the ideal volatge source). I run noise and pnoise simulation.
Results are same, that at 25-GHz, output noise equals 164V^2/Hz.
But I found in "noise parameter" output, total noise of M1 is 131.9V^2/Hz, that does not equals 164.
in "noise contribute" output, total noise of M1 is 164V^2, there are some extra items: M1.rg M1.rb M1.rs.
It seems M1.rg M1.rb M1.rs are gate, bulk, source resistance thermal noise, but if it were right, what is /M1 with para rs (value = 7.79e-18), and why para of "M1.rg .rb .rs" are rn? what is rn?
also why M1.rg .rb .rs does not appear in "noise parameter" output?
Thanks for patience!
( I think noise parameter and noise contribute are different, but don't know details, and there are too many cadence help documents I can't find the one I need.)