Amplifier noise temperature
Consider first the noise representation of the antenna and the low noise amplifier (LNA) shown in Fig. 2.15.
The available power gain of the amplifier is denoted as G, and the noise power output, as Pno.
For the moment we will work with the noise power per unit bandwidth, which is simply noise energy in joules as shown by Eq.
The input noise energy coming from the antenna is
N0,ant = kTant