Title :
Design of Doherty Power Amplifiers for Handset Applications
Author :
Kang, Daehyun ; Choi, Jinsung ; Kim, Dongsu ; Kim, Bumman
Author_Institution :
Dept. of Electr. Eng., Pohang Univ. of Sci. & Technol. (POSTECH), Pohang, South Korea
Abstract :
In this paper, we analyze the power drive of a Doherty power amplifier (PA), and introduce a technique for proper input dividing without a coupler. For the proper Doherty operation, we place a phase compensation circuit at the input of the carrier amplifier. We also propose an output matching of Doherty PA to reduce the number of matching components, and to match the output impedances to enhance efficiency and linearity in consideration of the uneven input drive. The PA circuit is fabricated using a 2-μm InGaP/GaAs heterojunction bipolar transistor process and combined for Doherty operation using merged lumped components. For the IEEE 802.16e m-WiMAX signal, which has a 9.54-dB crest factor and 8.75-MHz bandwidth, the PA has an error vector magnitude of 3% and a power-added efficiency of 40.2% at an output power of 26 dBm.
Keywords :
III-V semiconductors; MMIC amplifiers; WiMax; gallium arsenide; heterojunction bipolar transistors; impedance matching; indium compounds; microwave power amplifiers; mobile handsets; wide band gap semiconductors; Doherty power amplifier design; IEEE 802.16e m-WiMAX signal; InGaP-GaAs; MMIC; bandwidth 8.75 MHz; carrier amplifier; coupler; crest factor; efficiency 40.2 percent; error vector magnitude; heterojunction bipolar transistor process; merged lumped components; monolithic microwave integrated circuit; output impedance matching; phase compensation circuit; power-added efficiency; size 2 mum; Bandwidth; Coupling circuits; Gallium arsenide; Heterojunction bipolar transistors; Impedance matching; Linearity; Operational amplifiers; Power amplifiers; Power generation; Telephone sets; Doherty; efficient; handset; heterojunction bipolar transistors (HBTs); linear; monolithic microwave integrated circuit (MMIC); power amplifier (PA);
Journal_Title :
Microwave Theory and Techniques, IEEE Transactions on
DOI :
10.1109/TMTT.2010.2053074
