LNA circuit concept?

could some tell me about the cmos differential LNA datail?and
why compose two single stage LNA?s can be differential LNA

thanks

Increasing the number of stages in series in a LNA topology could decrease the noise factor. Differential stage is prefered to obtained better common mode noise rejection due to substrate coupling.

Rgds

These documents will help you to understand the concept.

Need so many points.

Added after 43 minutes:

Oh, sorry, I knew the free mirror just now.

Thanks very much!

using two 90 deg. coupler in the input and output obtain better matching and 3 db imorovement in comp point