Title :
Pulsed Load Modulation (PLM) Technique for Efficient Power Amplification
Author :
Jeong, Jinseong ; Wang, Yuanxun Ethan
Author_Institution :
Dept. of Electr. Eng., Univ. of California, Los Angeles, CA
Abstract :
A new concept of pulsed load modulation (PLM) is introduced for efficient power amplification. The proposed technique allows the power amplifier (PA) to maintain maximum efficiency until the output power of the amplifier is backed off by 6 dB. The PLM amplifier contains two pulse-biased PAs connected with a lambda/4 transmission line and a high- Q bandpass resonator. For maximum efficiency and linearity, the load impedance of the amplifier is digitally modulated using the switched-resonator concept. A prototype amplifier is implemented using two PAs and a diplexer for the 1.87-GHz band. The measured efficiency of the amplifier at peak output power is 51%. Compared with 25.5% of the conventional class-B amplifier, the PLM amplifier obtains an improved efficiency of 38% at 6-dB output power back-off.
Keywords :
UHF power amplifiers; pulse modulation; 6-dB output power back-off; frequency 1.87 GHz; power amplification; power amplifier; pulsed load modulation technique; Digital modulation; Impedance; Linearity; Power amplifiers; Power generation; Power measurement; Power transmission lines; Prototypes; Pulse amplifiers; Pulse modulation; Digital control; linear amplifier; load modulation; nonconstant envelope modulation; power efficiency; switched resonator;
Journal_Title :
Circuits and Systems II: Express Briefs, IEEE Transactions on
DOI :
10.1109/TCSII.2008.2001986
