Title :
Effects of different VDD-drives in ET & EER transmitters
Author :
Rautio, Timo ; Harju, Henri ; Hietakangas, Simo ; Rahkonen, Timo
Author_Institution :
Univ. of Oulu, Oulu
Abstract :
Envelope tracking (ET) technique transmitter employing a linear 0.5 W 1 GHz LDMOS PA (power amplifier) is studied. Four different methods for supply voltage modulation are discussed and measured results are given. Results show improvement both in efficiency and linearity when predistortion of the supply voltage is added. The same linear amplifier was used also in an envelope elimination and restoration (EER) system, and measurements show significant improvement in the linearity compared to the envelope tracking system, with no notable loss in the efficiency. Also the effect of feedthrough to the linearity was much lower than with a Class E PA in the same transmitter configuration.
Keywords :
power amplifiers; LDMOS power amplifier; VDD-drive; envelope elimination-and- restoration system; envelope tracking technique; frequency 1 GHz; power 0.5 W; supply voltage modulation; DC-DC power converters; Delay; Envelope detectors; Linearity; Power amplifiers; Power system restoration; Predistortion; Radio transmitters; Radiofrequency amplifiers; Voltage; LDMOS; Predistortion; linearity; power amplifier;
Conference_Titel :
Norchip, 2007
Conference_Location :
Aalborg
Print_ISBN :
978-1-4244-1516-8
Electronic_ISBN :
978-1-4244-1517-5
DOI :
10.1109/NORCHP.2007.4481031
