What type of power amplifier good for amplification signal with very low input power about -120dBm and high gain about 30dB?
It is used in GNSS receiver.
GNSS satellite system use CDMA modulation, so the circuit needs a linear amplification.
At this low output power level (+10dBm) the amplifier efficiency probably is not such important, so a Class-A Power Amplifier would be a good option getting good linearity and high gain.
Yes, I was mistaken.
For design such a low output power, is there a procedure to do it? I tried to do it as the way to design a normal power amplifier but because Pout is very low and therefore Rload from the formula Pout = Vdd^2/(2RLoad) is very very large about tens giga ohms.
I don't know why it is wrong?
Assuming that the output voltage swings between 0 and 2Vdd and it is a sinusoidal.
=> P = Vrms^2/Rload = (Vdd/sqrt(2))^2/Rload = Vdd^2/(2Rload).
Yes, the load resistance that I calculated is the one we get after impedance transformation network.
For example, with 50 ohms load we can make it up to 10 Gohms with impedance transfomation network.