RF-input load modulated balanced amplifier

This work presents a load modulated balanced amplifier (LMBA) that directly amplifies a modulated RF input. The architecture is based on the recently proposed LMBA technique, in which a control signal applied at the output hybrid of a balanced amplifier is used to modulate the apparent load impedance of the two main devices. Here, we eliminate the need for an externally-generated control signal. Instead, the control signal is directly and simply synthesized from a modulated RF input, allowing the architecture to function directly as an RF-input / RF-output power amplifier. The technique is demonstrated at 700-850 MHz with a peak efficiency of 63.2% at peak CW output power of 41.7 dBm, and 47.1% at 6 dB back-off.