rf power transistor zout

How to calculate Zout of Power Transistor if S parameter of the transistor is given, and its need to match to 50 oham line, no other information is given ?

Thanks.

Zout = 50*(1 + S22)/(1 - S22)

Please refer the calculation from link below
https://www.edaboard.com/ftopic341445.html

Matching to 50 Ohm can be accomplished by using smith chart.

But you don't need the S22 to deliver the "power" from this transistor because S-parameters are small signal parameters and they can't be used in power applications.
Instead, optimum output impedance is used to calculate the power that will be deleivered by the power transistor