Considerations for Developing a Highly Efficient, High-power Shortwave AM Transmitter

This paper describes a study on high power short-wave AM transmitter with high efficiency. First, we fabricated a new power amplifier operating at short-wave band (3M-30MHz) using RF MOSFETs and a new output circuit for obtaining high efficiency. Next, we proposed a new power combiner with excellent linearity by tuning the transmitter output circuit including stray capacitance and inductance. In addition, we proposed an evolutional short-wave AM transmitter since conventional MF band digital AM modulation method can not be introduced because of losses caused by parasitic diode of RF MOSFETs.