Title :
Efficient and wideband envelope amplifiers for envelope tracking and polar transmitters
Author :
Kimball, Don ; Yan, Jonmei J. ; Theilmanrr, P. ; Hassan, Mehdi ; Asbeck, P. ; Larson, Lawrence
Author_Institution :
Electr. & Comput. Eng. Dept., Univ. of Califomia, San Diego, La Jolla, CA, USA
Abstract :
Envelope tracking provides the potential for achieving high efficiency in power amplifiers for next generation wireless transmitters with high peak-to-average ratio signals such as OFDMA. Envelope modulators with high fidelity, high efficiency and wide bandwidth are critical enablers for the widespread application of envelope tracking. This presentation reviews the development of various envelope amplifiers for applications in basestation and handset power amplifiers. Requirements of voltage swing, bandwidth, and accuracy are first described. Various technologies for envelope modulators achieving voltages as high as 50V are presented, for operation in basestations with Si-LDMOS, HVHBT, GaN RF power transistors. CMOS-based Si envelope modulator ICs for operation in wireless handsets are also discussed. Envelope tracking microwave power amplifiers that achieve overall efficiency greater than 45% for LTE in handsets and greater than 64 % efficiency in basestations are presented.
Keywords :
CMOS integrated circuits; gallium compounds; microwave power amplifiers; next generation networks; power transistors; radio transmitters; silicon; wide band gap semiconductors; wideband amplifiers; CMOS; GaN; GaN RF power transistor; HVHBT; LTE; Si envelope modulator IC; Si-LDMOS; bandwidth; envelope tracking; microwave power amplifier; next generation wireless transmitter; peak-to-average ratio signal; polar transmitter; voltage swing; wideband envelope amplifier; wireless handset; Modulation; Multiaccess communication; Peak to average power ratio; Power amplifiers; Radio frequency; Spread spectrum communication; Switches; 700 MHz; 800 MHz; LTE; WCDMA; band 14; efficiency; envelope tracking; gallium nitride; power amplifier;
Conference_Titel :
Power Amplifiers for Wireless and Radio Applications (PAWR), 2013 IEEE Topical Conference on
Conference_Location :
Santa Clara, CA
Print_ISBN :
978-1-4673-2915-6
Electronic_ISBN :
978-1-4673-2931-6
DOI :
10.1109/PAWR.2013.6490173
