Broadband Doherty power amplifiers

In this paper, the transformer-less load-modulated (TLLM) architecture for designing broadband Doherty amplifiers is presented. In this architecture, the quarter-wave impedance transformers of the Doherty amplifier are not used. As a result, the design will be much more compact and large operational bandwidths can be obtained. The simulation results for an amplifier implemented using this architecture shows that drain efficiency of higher than 47% is obtainable at 6dB power back-off in 1.7-2.8GHz frequency range (50% fractional bandwidth).