Title :
A Wideband CMOS/GaAs HBT Envelope Tracking Power Amplifier for 4G LTE Mobile Terminal Applications
Author :
Hassan, Muhammad ; Larson, Lawrence E. ; Leung, Vincent W. ; Kimball, Donald F. ; Asbeck, Peter M.
Author_Institution :
Dept. of Electr. & Comput. Eng., Univ. of California at San Diego, La Jolla, CA, USA
fDate :
5/1/2012 12:00:00 AM
Abstract :
A high-efficiency envelope tracking power amplifier for long-term evolution (LTE) handset mobile terminals is presented. The envelope amplifier consists of a wideband buffered linear amplifier as a voltage source and a hysteretically controlled switching amplifier as a dependent current source. The linear amplifier has a high current drive capability of approximately 500 mA while consuming only 12 mA of quiescent current. The impact of envelope shaping on system efficiency and stability is investigated. The envelope amplifier is implemented in a 0.15- μm CMOS process and tested with a GaAs HBT RF power amplifier. For a 20-MHz LTE signal with 6.6-dB peak-to-average power ratio, an overall efficiency of 43% is achieved at 29-dBm RF output power level with relative constellation error below 1.9% after digital pre-distortion.
Keywords :
4G mobile communication; CMOS analogue integrated circuits; III-V semiconductors; Long Term Evolution; gallium arsenide; heterojunction bipolar transistors; power amplifiers; wideband amplifiers; 4G LTE mobile terminal application; CMOS process; GaAs; HBT RF power amplifier; LTE handset mobile terminal; LTE signal; Long-Term Evolution; constellation error; current 12 mA; current drive capability; digital predistortion; envelope shaping; frequency 20 MHz; high-efficiency envelope tracking power amplifier; hysteretically controlled switching amplifier; quiescent current; size 0.15 mum; system efficiency; system stability; voltage source; wideband CMOS HBT envelope tracking power amplifier; wideband buffered linear amplifier; Delay; Power generation; Radio frequency; Resistors; Sensors; Strontium; Switches; Envelope shaping; envelope tracking (ET); long-term evolution (LTE); polar transmitter;
Journal_Title :
Microwave Theory and Techniques, IEEE Transactions on
DOI :
10.1109/TMTT.2012.2187537
