general LNA question

[ch898230]

general question regarding low loss amplifier (LNA). To calculate gain on LNA, do I account for input and output return loss and gain parameter on the LNA specification? Such that gain of amplifier is gain - input and output return loss?

 

[BigBoss]

Which Gain you talk about ?? There are few types.
This page explains very well what I mean.

Calculate power gain from two-port S-parameters - MATLAB powergain

This MATLAB function calculates the transducer power gain of the 2-port network by:...

www.mathworks.com

 

[vfone]

general question regarding low loss amplifier (LNA).

LNA abreviation is coming from Low Noise Amplifier.

Even this is about small signal gain, the best to describe the gain of the LNA in a 50 ohms environment, is power gain.
Gain(dB) = Output power (dBm) - Input power (dBm)

 

[JonathanC]

As I remember the input impedance is much more important to an LNA and the LNA gain is independent to S22. Gamma output is derived from S11 and Gamma load should be conjugate matched with Gamma output.

 

[BigBoss]

As I remember the input impedance is much more important to an LNA and the LNA gain is independent to S22. Gamma output is derived from S11 and Gamma load should be conjugate matched with Gamma output.

This is not correct. Since \[ S_{12}\neq0 \] all 4 parameters will contribute into Gain Calculation.
Refer to my previous post.