| With the progress of society and the rapid development of productive forces, the requirement of communication technology is higher and higher. Researchers focus on RF power amplifier which accounts about35%cost of wireless communication equipment, and its linearity and efficiency are always the emphases. The information transmission technology of modern communication system is developed rapidly aimed at multi-carrier, broad band and PAR. With these transmission technologies, high linearity of RF power amplifier is necessary. Therefore, the linearization methods are needed to improve the linearity and the efficiency. There are several power amplifier linearization methods available which can be classified mainly as back off, feedforward, LNIC, predistortion and so on. Analog predistortion technology is used in this dissertation.First, there would be introductions on the nonlinearity characteristics of power amplifier, linearity index of power amplifier and the basic principles of linearity technology. Then the analog predistortion and power divider theory are analyzed and simulated. After that, we will discuss the Doherty power amplifier’s principle and structure in detail, including the simulation of traditional symmetrical Doherty power amplifier and non-symmetrical Doherty. The simulation results indicate non-symmetrical Doherty power amplifier’s efficiency and linearity are improved. Last, a simulation of the complete predistortion power amplifier is done, which indicates that predistortion power amplifier’s linearity is significant improved. |
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