Low Noise Amplifier problem P1dB and NF

[AbhayK]

Hey Guys,
I have been designing a Low Noise Amplifier from 1 to 3 GHz. I am searching for a transistor for my work. Earlier I had used ATF54143 for the design. My goal is to achieve 30K of noise temp throughout the band and its P1dB should be +20dBm atleast.
ATF54143 works fine till 2 GHz (~30K from 1 to 2 GHz). The noise temp in a two stage LNA drastically increases further till 3 GHz to 60K.
FHX40LG looks good device for low noise than ATF54143. But its P1dB at 12 GHz itself is +10dBm. May be it will have still lower at 3GHz.

Does anyone knows about any transistor which is low noise (0.2 to 0.3 dB) AND has a good P1dB (atleast +20dBm)????

Thanks...:grin:

 

[tony_lth]

what is the gain requirement?
P1db can be got by cascade two or three stages.
But your NF is really tough.

 

[jiripolivka]

Typical LNAs are designed for the best NF which often limits the amplifier linearity to low-level signals. Amplifier final stage is responsible for a high P-1 dB. Distribute LNA gain between the first stage having a low NF, and second stage with a high P-1 dB for best results.
Both parameters can rarely be met in one stage.

 

[BigBoss]

In this bandwidth (1-3GHz) ,it's really tough to realize 0.2dB NF and +20dBm P1dB overall band..