The Research Of Power Amplifer In L-band

With the rapid development of wireless mobile communication, improving the wireless communication efficiency is becoming a current problem that need to be solved. RF power amplifier is widely used in radar, communications, navigation, broadcasting and other fields. But what used the most is the mobile communication area. RF power amplifiers are used in both the base station and the mobile phone. As an important part of wireless communication system transmitter, RF power amplifier has obviously influence the performance index of transmitter system.It is becoming a high value subject to design high efficiency and linearity RF power amplifier in recent years. It has some incomparable advantages to apply the subject in the wireless communication system, and it has received widespread concern at home and abroad.In this paper, the transistor model is created and simulated by using the ADS software. And the corresponding method to the potential instability is proposed. On this basis, the design of matching network is carried on through the combination of load pull and Smith circle diagram. The input and output matching network is optimized by simulation. Finally, the harmonic balance method is used for nonlinear analysis.The main work of this paper is as follows:1. Introducing the background of this paper, including topic background, research meaning and the development status of RF power amplifier at home and abroad. With RF power amplifier design as the starting point, this paper has introduced theoretical basis of transmission line, RF power amplifier matching network and the different classification structure.2. Introducing the theory and parameters of RF power amplifier. The design flow of RF power amplifier is given using Freescale’s transistor MW6S20010. Then the RF power amplifier working in L-band is designed by using the ADS software, which is mainly used in wireless communication systems. In the process of nonlinear simulation, the harmonic balance simulation is introduced in detail. At last, the design goal is completed by using the load drawing method and the Smith circle graph matching.3. This paper has designed a high efficiency switching power amplifier. We have firstly designed a harmonic network for the second harmonic of short network and third harmonic of open network, and then design a reduced size of harmonic network. Using the load impedance of the load and the source impedance of the source to make a mutual iteration. The output and input circuit is designed combined with Smith circle diagram.Finally, according to the working principle of F class power amplifier, we have improved the efficiency of the amplifier by controlling the harmonic frequency, enabling the drain voltage waveform to a square wave and sinusoidal current with ADS software simulation and verification.