| With the development of modem society, more and more people long forconnecting with each other more quickly, booming development have happened inthe global mobile communication service, the requirement for expanding capacity ofthe communication system is becoming more and more urgent. In order to meethigher data radio and frequency spectrum efficiency, linear modulation formats arerecommended. These modulations lead to the change of signal envelope. And on theother hand, the modern communication system requires the higher linearity degree ofthe power amplifier itself is limited. So the linearization technique is preferred toimprove the linearity degree.The main body of this paper is the research and analysis of the RF predistortionlinearization, as there are several technologies to realize the linearization of RFpower amplifier. It includes two parts contents: firstly, it have studied the operationrules of parallel diodes predistorter, and verified its performance by designing a 10WWCDMA power amplifier, as a result the IMD3 and IMD5 is improved by 10dBmand 7dBm. Secondly, Doherty technology is analyzed for its application in thedesign of RF power amplifiers, except the classic Doherty power amplifier, a novelpredistortion linearization method using the gain expansion phenomenon in aDoherty amplifier is proposed in this chapter. At the end of this paper, a comparisonbetween above methods is proposed.In the finality, the problems requiring further studies are discussed. |
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