DPT. of Eletronics Engineering Univ. of Roma Tor Vergata
Franco Giannini was born in Galatina (LE) Italy, on November 9, 1944. He received the degree in Electronics Engineering, summa cum laude, in 1968, and in 2008 has been awarded with the Laurea Honoris Causa Scientiarum Technicarum by the Warsaw University of Technology, Poland.
Since 1980 is Full Professor of Applied Electronics, at the University of Roma Tor Vergata, and since 2001 Honorary Professor at the Warsaw University of Technology.
Prof. F. Giannini is or has been a consultant for various national and international industrial and governmental organizations, including the International Telecommunication Union and the European Union and is a member of many Committees of International Scientific Conferences.
Franco Giannini authored or co authored more than five hundred scientific papers on RF and MW technologies and applications.
The Doherty Amplifier: Past, Present & Future
Doherty Power Amplifier (DPA) is an old and fashionable configuration, introduced by W.E. Doherty in 1936 at the Bell Telephone Laboratories (BTL) of Whippany, New Jersey, for the realization of vacuum tube high-efficiency amplifiers, that has been successfully resurrected in the last decade, in agreement with the last sentence of the original paper. "The new amplifier is believed to offer a most logical and practical solution to the problem of efficient operation of high power transmitters", W.E. Doherty said and it has been demonstrated that it was a true prediction. Actually, the proposed solution has become today a hot research topic, representing the most suitable approach for implementing high efficiency transmitters, as the many published state-of-the-art results demonstrate. Even if actual systems are extremely different with respect to the first broadcasting ones, in terms of active device technologies, power levels and modulation schemes, the DPA seems, in fact, to remain the best candidate in order to realize Power Amplifiers (PA) for modern and future generations of wireless systems.
In this contribution, the evolution of the DPA from its original idea is presented, with the aim to stress its pros and cons. Starting from its original topology, the intrinsic limitations are reviewed together with new proposed solutions to overcome them, both in terms of architecture features and frequency limitations. Moreover, the theoretical aspects and the developed design methodologies are supported through experimental results, from MMIC or HIC realizations, highlighting different approaches and behaviors.