Development of a High efficiency HF power amplifier

This paper describes development of a High efficiency HF power amplifier. We fabricated a new wideband power amplifier operating at short wave band (3 MHz-26 MHz) using class-E amplifier and obtained a high output power efficiency of 74% at 25.5 MHz that is a target performance by controlling the shunt capacity for wideband operation. In addition, the low loss characteristic of about 0.4 dB and under and wideband characteristics was obtained by employing the balun using the transformer with coaxial cables and output circuit combiner tuned including stray capacitance and inductance.