2200 W High-Efficiency Amplifier Module Covering 325 MHz and 352 MHz Applications

After developing a 352 MHz 1600 W RF power amplifier with the ART2K0FE LDMOS transistor from Ampleon, the question was whether we could increase this power with the newer ART2K5TPU transistor from Ampleon with a comparable efficiency. In addition to the 352 MHz target, there is also a desire to find a configuration for 325 MHz, and if possible even a combination of both frequencies. The amplifier section of the modular LE029 amplifier platform is used as a starting point. The LE029 platform is designed for highly accurate reproduction, which is beneficial for power balancing in multiunit amplifier systems. During many tests and experiments it has become apparent that the circuit can be optimized to such an extent that a frequency range from 325 MHz to 352 MHz can be covered with an efficiency of more than 70 %. An observation has been made for 330 MHz, where a power of more than 2500 W can be achieved at 74 % efficiency. Further research showed that the planar balun structure appears to be responsible for this. A planned follow-up study will further investigate the extent to which this extreme optimum can be tuned to other frequencies.