| With the development of wireless communication, the frequency resourcesbecome more and more nervous. The power amplifier is the necessary component inradio frequency system and also a main part of nonlinear products, so it has theimportant actual meaning and the topic of the challenge to linearize the poweramplifier.In this paper we study the nonlinear characteristic of microwave power amplifiersystem. Introduce the basic principle of feedback, feedforward and pre-distortiontechnical to linearize. According to project I analyze a feedforward power amplifiersystem on the time and frequency field, we can conclude the relationship of all partsin this system when intermodulation distortions and other interference have beenremoved. Those provide a practical and valid method for designing a feedforwardpower amplifier. Utilizing these and for TD-SCDMA we research and develop thedivider, coupler, bridge and power amplifier at 2.35GHz. Finally I accomplished asimple and minimal structured feedforward power amplifier. Its measured third-orderintermodulation distortion (IMD) is -50dBc, which is 40dB greater than there is nolinearization technique. It proves the foundation of the theories and a reference priceof the project for getting a greater IMD. |
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