Title :
Analysis and design of a high-efficiency multistage Doherty power amplifier for WCDMA
Author :
Srirattana, N. ; Raghavan, A. ; Heo, D. ; Allen, P.E. ; Laskar, J.
Author_Institution :
Sch. of Electr. & Comput. Eng., Georgia Inst. of Technol., Atlanta, GA, USA
Abstract :
A comprehensive analysis of multistage Doherty amplifier, which can be used to achieve higher efficiency at greater back-off compared to the classical Doherty amplifier, is presented. A novel set of design equations for a generalized N-stage Doherty amplifier is introduced. For the first time, this technique is applied to the design of a WCDMA power amplifier (PA). The designed PA meets WCDMA requirements, and exhibits a power-added efficiency (PAE) of 34.5% at 6.dB back-off and 16.9% at 12 dB back-off. These PAEs are 2 times and 4 times better, respectively, than that of a single stage linear PA at the same back-off levels. The PA is capable of delivering up to 28.6 dBm of output power, and has a maximum adjacent channel power leakage ratio of -38 dBc and -51 dBc at 5 and 10 MHz offset, respectively. To the best of the authors´ knowledge, these represent the best reported results of a Doherty amplifier for WCDMA application in the 1.95 GHz band, to date.
Keywords :
UHF power amplifiers; 1.95 GHz; 10 MHz; 12 dB; 5 MHz; channel power leakage ratio; comprehensive analysis; design equation; multistage Doherty power amplifier; n-stage Doherty amplifier; power added efficiency; Equations; High power amplifiers; Impedance; Multiaccess communication; Power amplifiers; Power engineering and energy; Power engineering computing; Power generation; Power transmission lines; Transmission line theory;
Conference_Titel :
Microwave Conference, 2003. 33rd European
Print_ISBN :
1-58053-834-7
DOI :
10.1109/EUMC.2003.1262905
