Power amplifier design
Narrowband solutions may be preferable, with PI-network output tuning to "match" into your inductor/solenoid load, and the PI filtering will reduce distortion and random noise that may confuse your research results.  The amateur-radio people, for efficiency, may use class "C" on/off amplifiers, where PI-network filtering is required to meet harmonic interference restrictions; the "transmitters" have a 2-step process to change frequencies: at low power, tune the PI-network, then crank up the power. Given restrictions in radiated energy above 100KHz?, your 30 watt goal may have your local government investigating your research.

But if you want a broadband approach, something about like this







simulate this circuit &ndash; Schematic created using CircuitLab

Notice there is NO short-circuit protection. And this circuit is AC_coupled.

The power output may be easier, if the final NPN and PNP are large MOSFETS instead, with large Safe Operating Area. The capacitances of the MOSFETS will be a challenge to drive at 30MHz.