IIP3 improvement in a simple undegenerated CS LNA

[enzodtc]

Hi all,
As stated in the title I have issues with IIP3 for an undegenerated common source LNA.
The required IIP3 is at least 5 dBm and the maximum that this LNA can reach is about 3 dBm.
How can I improve the IIP3 without changing the circuit at all ?

 

[BigBoss]

You should improve the linearity by examining the optimum OP of the Transistor.
Check the curve Ids vs. Vgs and then differentiate this curve so find the gm vs. Vgs.
You will see a rising in this curve then a flat region after that falling region.
The transistor should work on this flat region. Second derivative of this curve will tell you second order nonlinearity. so on..
OP is the most important variable for this kind of circuits.

 

[enzodtc]

You should improve the linearity by examining the optimum OP of the Transistor.
Check the curve Ids vs. Vgs and then differentiate this curve so find the gm vs. Vgs.
You will see a rising in this curve then a flat region after that falling region.
The transistor should work on this flat region. Second derivative of this curve will tell you second order nonlinearity. so on..
OP is the most important variable for this kind of circuits.

Thank you,
How can I find the derivative in CADENCE Virtuoso?

 

[D.A.(Tony)Stewart]

Not sure if this is useful https://people.engr.tamu.edu/s-sanchez/Heng_LNA.pdf or accurate

Thank you,
How can I find the derivative in CADENCE Virtuoso?

I just found this search result (deriv(i("/M0/D" ?result "dc"))