VHF broadband power amplifier design
|School||University of Electronic Science and Technology|
|Keywords||power amplifier broadband matching transmission line transformers output power nonlinearity|
Power amplifiers play an important role in the communications equipment. In the transmitter, power amplifier will be needed to amplify the signal before they can be send by the antenna; in the receiving end, the weak received signal need to be amplified by the amplifier. The application of power amplifiers is extremely broad ,the study of the power amplifiers is significance.In this subject, A linear power amplifier worked in the band of 20MHz-90MHz with the out put power of 50 Watts was designed. The wide frequency bandwidth, big gain, and high out put power were required. In this paper, the basic theory of the power amplifier is firstly introduced ,the main technical indicators of power amplifier are introduced. It’s helpful to know much about the indicators in the work of designing power amplifier. The nonlinearity, which is very important in the designing of power amplifier, is discussed. The in-depth study of the theory is extremely necessary. Some questions, which are familiar in the amplifier designing, is discussed, and the solutions are given.The design of matching network is very important, and its quality determines the quality of the performance of power amplifier. In This subject, transmission-line transformer is used for impedance conversion. Simulation software such as the ADS is used in the design.In this paper, the process of the designing of the power amplifier is described. The matching circuit, bias circuit, control circuit are designed. After the assemblage of the power amplifier, the data are measured. The performance of the power amplifier is good as expected.