how can choose transistor in a power amplifier!

[kiyanmajd]

Hi guys,
I want to design an power amplifier,With the following specifications:

Frequency range 1400 ... 1600 MHz
Input power 1W(typical) , 2W (Max.)
Output power P1dB min. 45 W (CW)
Saturation power Typ.60W
IM3 @ 45W PEP min. -30 dBc
efficiency 50% @ 45W
Gain (small signal) Typ. 17 dB
Supply voltage +28 V DC
Quiescent current typ. 550 mA
Current consumption 3.5A @45W, max. 5.5 A @ 60W

Applications of this PA is Digital broadcast systems (DAB, DVB) and COFDM systems using modulation types QPSK, QAM ...
now My question is that:
1. how to choose transistor for this power amplifier?
2. There are so many class types for RF PA.Which class type should I use?

 

[FvM]

Only linear PAs (class-A or class-AB) are suitable for QAM and similar modulation schemes involving amplitude information.

Major manufacturers have device overviews sorted by frequency and power range.

 

[BigBoss]

In these power ranges, GaN transistors are very popular nowadays.
Cree,Nitronex,Triquint. Macom...