Title :
Application of Doherty Amplifier as a Predistortion Circuit for High Power Amplifier Linearization
Author :
Lee, Yong-Sub ; Lee, Mun-Woo ; Jeong, Yoon-Ha
Author_Institution :
Dept. of Electron. & Electr. Eng, Pohang Univ. of Sci. & Technol., Pohang
Abstract :
This paper presents the application of Doherty power amplifier (DPA) as predistortion circuit for linearization of high PA. When the DPA is employed to the driver amplifier, its nonlinearity is used as predistorted components to cancel the strong nonlinearity of the main amplifier. To verify proposed method, the DPA is implemented with two 30-W Si LDMOSFETs and teseted with a 180-W main amplifier at wideband code division multiple access (WCDMA) band of 2.14 GHz. For a two-tone signal with 2-MHz tone spacing and a one-carrier WCDMA signal, the significant cancellation of the 3rd and 5th-order intermodulation (IM3 and IM5) components and a superior adjacent channel leakage ratio (ACLR) improvement are achieved.
Keywords :
MOSFET circuits; UHF amplifiers; code division multiple access; intermodulation distortion; linearisation techniques; power amplifiers; Doherty amplifier; LDMOSFET; UHF amplifiers; adjacent channel leakage ratio; driver amplifier; frequency 2.14 GHz; intermodulation cancellation; power 180 W; power 30 W; power amplifier linearization; predistortion circuit; wideband code division multiple access; Broadband amplifiers; Driver circuits; High power amplifiers; Linearity; Microwave amplifiers; Microwave circuits; Multiaccess communication; Power amplifiers; Predistortion; Repeaters;
Conference_Titel :
Microwave Conference, 2008. EuMC 2008. 38th European
Conference_Location :
Amsterdam
Print_ISBN :
978-2-87487-006-4
DOI :
10.1109/EUMC.2008.4751630
