Title :
Doherty amplifier design for 3.5 GHz WiMAX considering load line and loop stability
Author :
Medina, M. A Yarleque ; Schreurs, D. ; Angelov, I. ; Nauwelaers, B.
Author_Institution :
Div. ESAT-Telemic, Katholieke Univ. Leuven, Leuven
Abstract :
Legacy Doherty amplifier is characterized by using a larger transistor for the peak amplifier such that this reaches saturation with a smaller excitation signal. However due to device availability and modelling considerations, this is not often feasible. In this paper, the design and measurement of a Doherty amplifier utilizing only single sized device is realized. Unlike previous research works, intrinsic load line is utilized to tune the offset lines, as well as to verify the actual dynamic load principle. Stability aspects are covered for this type of amplifier, which are not normally included in earlier works. Finally an assessment of its applicability and benefits for WiMAX at 3.5 GHz is realized using a class AB amplifier as a comparison basis.
Keywords :
WiMax; circuit stability; circuit tuning; microwave amplifiers; Doherty amplifier design; WiMAX; amplifier stability; dynamic load principle; frequency 3.5 GHz; offset line tuning; Circuit stability; Gallium arsenide; Microwave amplifiers; Microwave integrated circuits; OFDM; Peak to average power ratio; Power amplifiers; Power generation; Size measurement; WiMAX;
Conference_Titel :
Microwave Integrated Circuit Conference, 2008. EuMIC 2008. European
Conference_Location :
Amsterdam
Print_ISBN :
978-2-87487-007-1
DOI :
10.1109/EMICC.2008.4772344
