Conception et realisation d'un amplificateur RF a haut rendement energetique.

摘要

The general purpose of this work focuses on this investigation for the improvement of the performance of power amplifiers for wireless communications technology. Power amplifiers are designed with different and original architectures. Among these architectures, we can find the LINC and the Doherty architectures. The LINC architecture allows converting a modulated signal into two constant envelope signals with phase modulation. Then, it's up to the combiner to sum these two signals to reproduce the original signal amplified. The work developed aimed the wideband matching network and optimizing the efficiency of Chireix combiner. Several wideband matching techniques were identified and examples were simulated for the purpose of confirming the theory. Other works have been developed to propose a new model describing the efficiency of the Chireix combiner. This model enables more flexible architecture. Indeed, the efficiency of the combination can achieve the theoretical maximum even if the output impedance of the power amplifier is different from the normalized impedance. The ADS software is used to validate the results of this analytical approach. The result, which follows, is to provide a way to design a combiner that achieves maximum efficiency regardless of the output impedance of the power amplifier. Another contribution is made about designing a Doherty amplifier and obtaining a good efficiency while maintaining a threshold of linearity.;Key words: Chireix, combiner, LINC, Doherty, impedance matching, efficiency, power amplifier.