The latest GaN devices seem impressive, many rated at DC to 4GHz.
But the reality is whether impedance matching circuit can reach 50MHz to 3GHz bandwidth.
The problem is power efficiency and thermal dissipation.
Especially when you combine boost DC supply, you're not going to have a heat sink fitting into a cigarette pack size.
Best power efficient of RF device is at saturated power, but often SDR signals have high peak-to-average power ratio, and must be backed off so only the power peaks reach saturation.
Seems alot of these challenges are addressed with whats known as "class E" or drain modulation / polar modulation.