help for Class-C amplifier

hi everybody.
i want to design a C class amplifier in 2GHZ with 2watt output power.
i have found 2 transistors for that. first one converts 2watt output power to 300mwatt and second one converts it to 30mwatt and input source can gives 30mwatt as its output power. but the transistors' load impedances and source impedances are given in 7.5watt and 2.5watt output power,respectively. what can i do?
the seconde problem is that the impedances given in datasheet are different than i computed. for computing the real section of load impedance i compute (RL=VCC^2/2*Pout) and the result for VCC=26v and Pout=7.5watt is so different than in datesheet(for first transistor). now i dont know which one of these is right. i must design matching network for load impedance which datasheet gives or which the above formula gives (for computing the Img section of load impedance in this case i use the amount which datasheet gives)?
please guide me!
the transistors are PTB20082 and PTB20180

I can't understand the first question clearly.
About the 2nd question, the load you calculated is based on the loadline theory, which is the load of intrinsic current source. However, the package transfers this load to some value we don't know. So the best way is the loadpull measurement. The load written in the datasheet usually comes in this way, unfortunately, it's obtained under the bias condition of class AB (Icq=70mA). So you do not have any reference until you measure it under your bias condition.

i mean that the impedances which datasheet gives are measured in 7.5watts but i need the impedances values in 2watts.
can i use the impedances values in 7.5watts for 2watts which i need?

for each input/output power we plot impedance contour on smith chart.
it means that for one const power we have a impedance plot which gives us impedances at many frequencies.i want to know how to plot that and i think with Scattering Parameters we can plot, but i dont know how!

Added after 4 minutes:

please look at this topic

https://www.edaboard.com/ftopic401613.html

Hi Ahmadloo, :)

firstly you need to get things written around the right way so that you understand what is happening and others can easier understand what you are trying to ask :)

what you described above was a multistage attenuator not a multistage amplifier.
when describing a transmitter always start at the low power end
rephrasing you above statement it should read....

"my 30mW source is amplified to 300mW in the driver transistor stage. That 300mW drives the final transistor to an output of 2W.

Now you have an amp, not an attenuator ;) the fun in learning new things

for a given fixed frequency say your 2GHz, I wouldnt expect the impedance to vary as the drive level changed. that is .... say changing from 300mW drive to give 2W output, to say 800mW drive to give 7W output shouldnt have any significant effect on the input impedance of the transistor.

Dave

sorry for my bad English.

thanks a lot, but i think input/output impedences will vary as the drive level changes.

following pic shows that