This paper describes the design, development, and performance of a low cost, high-efficiency, 1000 Watt RF power amplifier (PA) for 27.12 MHz, operated from a 300VDC supply. The PA is built around a “symmetric Pair” of low cost RF power MOSFETs from Advanced Power Technology (APT). These transistors are from a new generation of high quality, commercial, HF/VHF high voltage silicon devices, in TO-247 packages. The paper addresses both the theoretical design and physical construction of the amplifier, along with a technical description of the RF power transistors themselves.
Transistorized RF Power Amplifiers operate from a low voltage DC source, usually about 50V or less. It is common to use a DC to DC converter rather than a linear regular to increase the system efficiency. This supply requires a down regulator when operated from AC mains and it is a significant portion of the overall cost of the RF amplifier system.