Title :
Optium design of Doherty amplifiers based on average power efficiency
Author :
Yang, Sanbing ; Liu, Taijun ; Ye, Yan ; Xu, Tiefeng
Author_Institution :
Coll. of Inf. Sci. & Eng., Ningbo Univ., Ningbo, China
Abstract :
This paper presents a design approach of Doherty amplifier, which is based on optimizing the average power efficiency instead of peak power efficiency by adjusting the offset lines located in the branches of the carrier and the peak amplifier. The back-off point of the Doherty amplifier, which can be shifted by tuning the offset lines, should be optimized according to the power probability distribution of the modulated signal so as to achieve the maximum average power efficiency. A Doherty amplifier is designed using Freescale´s MRF281S 4-W LDMOS FETs and the test signal is a TD-SCDMA signal at 2017.5MHz. The validation result of the Doherty amplifier show that the average power efficiency is 31.2 % at 9 dB back-off point. The power efficiency enhances 4.2% and 3.9%, respectively, comparing with 27% at the 6 dB back-off point and 27.3% at the 13 dB back-off point.
Keywords :
UHF amplifiers; UHF integrated circuits; code division multiple access; integrated circuit design; power amplifiers; Doherty amplifiers; Freescale´s MRF281S 4-W LDMOS FET; TD-SCDMA signal; average power efficiency; back-off point; frequency 2017.5 MHz; optimum design; peak power efficiency; power probability distribution; Design engineering; Design optimization; Distributed amplifiers; Educational institutions; Operational amplifiers; Power amplifiers; Probability distribution; Signal analysis; Signal design; Time division synchronous code division multiple access; Doherty amplifier; average power efficiency; back-off point; probability distribution;
Conference_Titel :
Information, Computing and Telecommunication, 2009. YC-ICT '09. IEEE Youth Conference on
Conference_Location :
Beijing
Print_ISBN :
978-1-4244-5074-9
Electronic_ISBN :
978-1-4244-5076-3
DOI :
10.1109/YCICT.2009.5382436
