Title :
A 30 W Cartesian Feedback Transmitter with 40 % Efficiency Incorporating an Inverted Doherty Amplifier
Author :
Cho, Hanjin ; Kim, Min-su ; Jeong, Jonghyuk ; Van, Ju-ho ; Jung, Sung-chan ; Park, Hyun-chul ; Lim, Kyung-hoon ; Kwon, Sungwook ; Kim, Jae Young ; Song, Sung Chan ; Park, Cheon-Seok ; Yang, Youngoo
Author_Institution :
Sch. of Inf. & Commun., Sungkyunkwan Univ., Suwon
Abstract :
We present a 30 W Cartesian feedback transmitter with an efficiency of 40 % and an adjacent channel leakage power ratio (ACLR) of -51 dBc for 859 MHz band pi/4-DQPSK applications. The high efficiency of the system was achieved by a significant efficiency improvement for the final amplifier stage using a load modulation technique. The implemented Cartesian feedback transmitter, using a Doherty power amplifier, exhibited a 3rd order inter-modulation distortion (IMD3) improvement of 27 dB for a two-tone signal at an output power level of 45 dBm. It also had ACLR improvement of 16.2 dB for the pi/4-DQPSK signal at an output power level of 45 dBm. The system performed with an efficiency as high as 40 % which was an improved value by about 7 % points as a consequence of the high efficiency characteristics of the inverted Doherty amplifier.
Keywords :
amplifiers; feedback; intermodulation distortion; transmitters; 3rd order inter-modulation distortion; Cartesian feedback transmitter; adjacent channel leakage power; inverted Doherty amplifier; load modulation technique; power 30 W; Baseband; Demodulation; High power amplifiers; Linearity; Nonlinear distortion; Output feedback; Power amplifiers; Power generation; Radiofrequency amplifiers; Transmitters; Cartesian feedback transmitter; high-power amplifier; inverted Doherty amplifier; linear transmitter;
Conference_Titel :
Microwave Conference, 2007. APMC 2007. Asia-Pacific
Conference_Location :
Bangkok
Print_ISBN :
978-1-4244-0748-4
Electronic_ISBN :
978-1-4244-0749-1
DOI :
10.1109/APMC.2007.4554960
