Title :
An extended Doherty amplifier with high efficiency over a wide power range
Author :
Iwamoto, M. ; Williams, A. ; Pin-Fan Chen ; Metzger, A. ; Chengzhou Wang ; Larson, L.E. ; Asbeck, P.M.
Author_Institution :
Dept. of Comput. & Electr. Eng., California Univ., San Diego, La Jolla, CA, USA
Abstract :
An extension of the Doherty amplifier architecture which maintains high efficiency over a wide range of output power (>6 dB) is presented. This extended Doherty amplifier is demonstrated experimentally with InGaP-GaAs HBTs at a frequency of 950 MHz. P/sub 1 dB/ is measured at 27.5 dBm with PAE of 46%. PAE of at least 39% is maintained for over an output power range of 12 dB backed-off from P/sub 1 dB/. This is an improvement over the classical Doherty amplifier, where high efficiency is typically obtained up to 5-6 dB backed-off from P/sub 1 dB/. Generalized design equations for the Doherty amplifier are derived to show a careful choice of the output matching circuit and device scaling parameters can improve efficiencies at lower output power.
Keywords :
III-V semiconductors; UHF power amplifiers; bipolar transistor circuits; gallium arsenide; gallium compounds; heterojunction bipolar transistors; impedance matching; indium compounds; 39 to 46 percent; 950 MHz; InGaP-GaAs; InGaP-GaAs HBTs; device scaling parameters; extended Doherty amplifier; generalized design equations; high efficiency amplifier; output matching circuit; wide power range; Batteries; Circuits; Equations; High power amplifiers; Impedance; Operational amplifiers; Power amplifiers; Power generation; Power transmission lines; Telephone sets;
Conference_Titel :
Microwave Symposium Digest, 2001 IEEE MTT-S International
Conference_Location :
Phoenix, AZ, USA
Print_ISBN :
0-7803-6538-0
DOI :
10.1109/MWSYM.2001.967044
