| Microwave linear power amplifiers are the hard-core of the transmitter, widely used in the wireless communications and military system areas ,and are playing a more and more important role in navigation,radar,mobile communications,satellite communications and so on. They are often required to output some powers at a point of frequency or within a range of frequencies; the performance of the power amplifiers already becomes the key factor for restricting the capability and technique realizing of the whole transmit system.This paper firstly offers the gain distribution and design methods for all lever circuits in the base of the target desire and summarizes the methods of linear power amplifiers. Secondly this essay designs the bias circuits,stability and matching circuits using software ADS and Smith tool of the power amplifiers and presents the simulation results. Thirdly it includes the analysis of the dissipation of output matching circuits when we analyze the matching circuits, and receives the conclusion. Fourthly it designs the linearity circuit of the last lever power amplifier adopting the pre-distortion method. Fifthly this essay mentions the ways of improving the efficiency theories ,especially the application of the Doherty power amplifier technology and DC—DC direct current transform circuit besides of linear power amplifiers. Lastly it completes the practicality of power amplifier including considering the influence of electromagnetic compatibility (EMC) and accomplishes the debug and test work in the end. |
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