Title :
A microwave Doherty amplifier employing envelope tracking technique for high efficiency and linearity
Author :
Yang, Youngoo ; Cha, Jeonghyeon ; Shin, Bumjae ; Kim, Bumman
Abstract :
In this letter, we demonstrate a microwave Doherty amplifier employing an input signal envelope tracking technique. In the amplifier, the gate bias of the peaking amplifier is controlled according to the magnitude of the envelope. A 2.14-GHz Doherty amplifier is implemented using 4-W PEP LDMOSFETs, and an adaptive controlled gate bias circuit is constructed and the control shape is optimized experimentally. The performance of the microwave Doherty amplifier is compared with that of a class AB amplifier using one-tone, two-tone, and forward-link wideband code-division multiple access (WCDMA) signals. For a forward-link WCDMA signal, the measured power added efficiency (PAE) of the microwave Doherty amplifier is 39.4% at -30 dBc adjacent channel leakage ratio (ACLR), while that of the comparable class AB amplifier is 24.2% at the same ACLR level.
Keywords :
MOSFET circuits; UHF power amplifiers; circuit optimisation; code division multiple access; microwave power amplifiers; 2.14 GHz; 39.4 percent; 4 W; PEP LDMOSFETs; adaptive controlled gate bias circuit; adjacent channel leakage ratio; class AB amplifier; control shape optimization; envelope magnitude; forward-link wideband code-division multiple access signals; gate bias control; high efficiency; high linearity; input signal envelope tracking technique; microwave Doherty amplifier; one-tone WCDMA signals; power added efficiency; two-tone WCDMA signals; Adaptive control; Broadband amplifiers; Circuits; Linearity; Microwave amplifiers; Microwave theory and techniques; Multiaccess communication; Power amplifiers; Programmable control; Shape control;
Journal_Title :
Microwave and Wireless Components Letters, IEEE
DOI :
10.1109/LMWC.2003.817130
