Absolute theoretical maximum output power of a PA stage

Hi guys,

I'm designing a PA stage and would like to know how to determine what is the absolute theoretical maximum output power that I can get from the transistor into my load?

The transistor is part a submicron SiGe technology with a defined BV, ft, fmax and optimum current density. At first glance it depends of the maximum possible VCE across the transistor as well as the maximum current (I_max) that the transistor can hold, but this approach overlooks the operating frequency I guess, i.e. the transistor will not deliver the same output power at 10 GHz than at some frequency near its ft/fmax if I am correct?

Could someone provide maybe some insight into how to determine this? Some useful books/articles/references with some basic analysis would be really useful to me.

Many thanks in advance,

MK