PAE of Class A power Amplifier

Dear All,

I have the following question related to the PAE of Class A power amplifier. Useful ideas,hints are welcome.

A single-stage power amplifier operates at 30GHz and and is perfectly matched at the input. It can at maximum deliver 20dBm power to a 50Ohm load. The amplifier is operating in class A with Vd=2V and Id=200mA. The PAE is measured to be 22.5%.
?In order to increase the gain, two of similar amplifiers are used in cascade. What is the total PAE?
?In order to increase the efficiency, you are allowed to change the bias condition (both VD and VG) of the amplifiers separately. Motivate what you would do and how much the maximum PAE can be improved.

Looking forward to hear from you.

BR,
SC

What is your gain and output power? You can simply calculate it by PAE=RF output power/DC power consumption.

Hi

PAE is RF power out - RF power in / (Vdc*Idc)
Eff is RF power out / (Vdc*Idc)

So Because I dont know what is your Gain lets talk about Eff.

EFF will be max 22.5% and if Gain is low so maybe it will decrease... (please put u numbers and do calculation)

Regarding to the second question u can change bias conditions when last stage should be with best EFF...

David