anyone design lna in ansoft desinger?

[jeanjean]

i design a lna (6-7GHz) in ansoft desinger.

using 36077.s2p in the software for input and outpur match .

in simulation the noise is only 0.5dB

In fact the noise is 1.4dB, but S11,S21 is similar to the solution in software.

i want to know what made the noise worse.

thank

 

[DonJ]

S-parameters are linearised and usually easy to simulate.
Noise performance depends also on nonlinear phenomena.
0.5dB FN sounds really good (too good to be true (?) )

A.T.B

Added after 47 seconds:

S-parameters are linearised and usually easy to simulate.
Noise performance depends also on nonlinear phenomena.
0.5dB NF sounds really good at this freq. range (too good (?) )

A.T.B

 

[xtasa]

LNA with NF in range of 0.5 dB is an really good results. Difference between simulation and practical realization is not rear thing. Please add attachment with schematic or file to see how LNA looks like. Maybe is problem in quality some componet like it is bias chokes. Its bad Q quality produce very big noise it is like R connected to the input of amplifier. Second maybe it is model for LNA used in situation too simple to describe real realization?
Practicaly in AD is good agreement between design and realization if it is good model for simulation and optimization in vicinity 0.1-0.2dB. Please make an additional check!

GL XTASA