Title :
900 MHz pulse-width-modulated class-s power amplifier with improved linearity
Author :
Maier, Simone ; Wiegner, Dirk ; Zierdt, Mike ; Kuebart, Wolfgang ; Seyfried, Ulrich ; Haslach, Christoph ; Pascht, Andreas ; Maroldt, Stephan ; Quay, Rüdiger
Author_Institution :
Alcatel-Lucent Bell Labs., Stuttgart, Germany
Abstract :
The following paper presents a novel 900MHz pulse-width-modulated current-mode class-S power amplifier. The conversion from an analog to a digital signal, which can be handled by the subsequent switch-mode-stage, is implemented using a fast pulse-width-modulator. The complete class-S amplifier is characterized using clipped WCDMA signals with 5MHz and 80MHz bandwidth, respectively. For the 5MHz signal, the measured spectrum at the amplifier´s output shows good EVM of <; 12% (approx. 1.5% degradation assumed for class-S PA) and also meets the 3GPP ACLR requirements within 9dB input power range. The capability to support large signal bandwidths is demonstrated, using an 80MHz WCDMA signal, thus meeting the expectations on class-S amplifier for the first time with respect to signal bandwidth.
Keywords :
UHF power amplifiers; VHF amplifiers; pulse width modulation; 3GPP ACLR requirements; analog-digital signal; bandwidth 5 MHz; bandwidth 80 MHz; clipped WCDMA signals; frequency 900 MHz; linearity improvement; pulse-width-modulated current-mode class-S power amplifier; subsequent switch-mode-stage; Bandwidth; Clocks; Frequency measurement; Linearity; Pulse width modulation; Resonator filters; Switches; Class-S amplifier; PWM; large signal bandwidth; linearity; switch-mode operation;
Conference_Titel :
Microwave Symposium Digest (MTT), 2011 IEEE MTT-S International
Conference_Location :
Baltimore, MD
Print_ISBN :
978-1-61284-754-2
Electronic_ISBN :
0149-645X
DOI :
10.1109/MWSYM.2011.5972780
