Search for cell phone PA chips, order some samples and use reference design from producer of chip.
That was my approach couple years ago. Target application was biological study for cell RF.
In the mean time your quick solution can be one from my friend Adam 9A4QV ->
look for ->
HackRF TX amplifier modification
This part is not necessary because Lime have no Bias-T option, so leave the board as is
and apply DC power on standard pads...