How to increase P1dB of PA?

I want design PA that output power is 120W.
I use 3 stage amplifier for driver and 2 CGH400120F as PA in balance form.
how I can increase the p1dB of this design?
thanks

The ultimate P1dB you will get depends on the chosen output devices. In a balanced configuration you can theoretically get 3dB higher P1dB than the spec of each device. In practice, you will need to minimize losses in the output circuit and match your devices for highest compression point. This will usually neccessitate subotimal gain and reflections, but the latter is of no serious concern as the hybrid will swamp reflected power.

The saturated output power of a single CGH400120F transistor is 120W, so the linear output power when using two transistors in balance configuration, will be lower than 100W.

Initially see if you get good CW saturated output power (and good efficiency) when use two transistors.
If everything is fine, tune slightly the Idq and see the P1dB variation.