Design of wide-bandwidth envelope-tracking power amplifiers for OFDM applications

Author

Wang, Feipeng ; Yang, Annie Hueiching ; Kimball, Donald F. ; Larson, Lawrence E. ; Asbeck, Peter M.

Author_Institution

Dept. of Electr. & Comput. Eng., Univ. of California, La Jolla, CA, USA

Volume

53

Issue

4

fYear

2005

fDate

4/1/2005 12:00:00 AM

Firstpage

1244

Lastpage

1255

Abstract

An efficiency-enhanced power-amplifier system design is presented based on wide-bandwidth envelope tracking (WBET) with application to orthogonal frequency-division multiplexing wireless local area network systems. Envelope elimination and restoration (EER) and WBET are compared in terms of the time mismatch sensitivity between the base-band amplitude path and the RF path, and it is demonstrated that WBET is much less sensitive than EER to these effects. An adaptive time-alignment algorithm for the WBET system is developed and demonstrated. The analysis and algorithm are verified by experimental results. The measurement shows that the peak drain efficiency of the complete system was 30% at a 2.4-GHz orthogonal frequency-division multiplexing output power of 20 dBm.

Keywords

OFDM modulation; power amplifiers; wireless LAN; 2.4 GHz; OFDM applications; adaptive time-alignment algorithm; envelope elimination; envelope restoration; orthogonal frequency-division multiplexing; power-amplifier system design; time mismatch sensitivity; wide bandwidth envelope tracking; wireless local area network; Algorithm design and analysis; Broadband amplifiers; Frequency division multiplexing; Frequency measurement; OFDM; Power amplifiers; Power measurement; Power system restoration; Radio frequency; Wireless LAN; Envelope elimination and restoration (EER); envelope tracking (ET); orthogonal frequency-division multiplexing (OFDM); power amplifiers; power tracking; time alignment; wireless local area network (WLAN);

fLanguage

English

Journal_Title

Microwave Theory and Techniques, IEEE Transactions on

Publisher

ieee

ISSN

0018-9480

Type

jour

DOI

10.1109/TMTT.2005.845716

Filename

1420754