New generation of multi-step Doherty amplifier

This contribution presents an innovative solution to drastically increase the output power range in which the Doherty Power Amplifier shows a high and flat efficiency behaviour. The proposed topology and its main theoretical guidelines are shown and discussed. Moreover, the potentialities of the new idea and how it can solve some drawbacks in applications that manage signals with a peak to average power ratio greater than 7-8 dB are listened. The proposed idea has been validated performing several experimental measurements on an X-Band GaAs MMIC Doherty amplifier. In particular, the region of high and flat efficiency has been extended from 6dB to 11dB of output power back-off, without affecting gain and reached output power levels. As a result, a real average efficiency improvement of about 81% in the added 5dB of output back-off has been achieved.