Optimization for Envelope Shaped Operation of Envelope Tracking Power Amplifier

Author

Kim, Dongsu ; Kang, Daehyun ; Choi, Jinsung ; Kim, Jooseung ; Cho, Yunsung ; Kim, Bumman

Author_Institution

Dept. of Electr. Eng., Pohang Univ. of Sci. & Tech nology (POSTECH), Pohang, South Korea

Volume

59

Issue

7

fYear

2011

fDate

7/1/2011 12:00:00 AM

Firstpage

1787

Lastpage

1795

Abstract

This paper describes the analysis of an optimized envelope shaping function for the envelope tracking power amplifier (ET PA) and its implementation. The proposed shaping function, which is sweet spot tracking with crest factor reduction, improves the efficiency and output power of the power amplifier (PA), as well as its linearity. For an accurate simulation of the supply modulator, an equivalent model of the PA under the envelope shaping is suggested. To achieve high efficiency and wide bandwidth, the CMOS supply modulator has a hybrid structure of a switching amplifier and a linear amplifier. The fabricated ET PA delivers higher efficiency and better linearity than standalone PA for the wideband code division multiple access and long-term evolution signals.

Keywords

CMOS integrated circuits; code division multiple access; power amplifiers; CMOS supply modulator; crest factor reduction; envelope shaped operation; envelope tracking power amplifier; linear amplifier; long-term evolution signals; sweet spot tracking; switching amplifier; wideband code division multiple access; Capacitance; Heterojunction bipolar transistors; Linearity; Modulation; Peak to average power ratio; Power generation; Switches; Crest factor reduction (CFR); envelope tracking (ET); polar transmitter; power amplifier (PA); sweet spot;

fLanguage

English

Journal_Title

Microwave Theory and Techniques, IEEE Transactions on

Publisher

ieee

ISSN

0018-9480

Type

jour

DOI

10.1109/TMTT.2011.2140124

Filename

5764508