Title :
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
fDate :
7/1/2011 12:00:00 AM
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;
Journal_Title :
Microwave Theory and Techniques, IEEE Transactions on
DOI :
10.1109/TMTT.2011.2140124
