Investigation Of Rf Power Amplifier Based On Software-Defined Radio

Software-Defined Radio (SDR) has been proposed as a new communication architecture in recent years. It has been recognized as the next major leap forward in wireless communications. Because it accords with the current thought of the communication development, it has become the focus of the research on the design of communication systems. Radio frequency power amplifiers have become more and more important with the development of the information technologies for wideband and high speed of wireless communications in the present and the future. The design about power amplifiers is much a challengeable topic, especially in the more complicated performance of modem communication systems. It is very significant making a thorough and careful study on the design of the power amplifier. The investigation of the radio frequency power amplifier based on SDR promotes the development of SDR. At the same time, SDR provides new techniques and methods for the design of power amplifiers.The paper has discussed deeply the power amplifier in SDR. And the present design methods and techniques of the broadband linear power amplifier are analyzed at large. The study of the power amplifier's performance characteristics is emphasized on broadband, linearity and efficiency.On the aspect of broadband, the design of the broadband power amplifier is summarized generally. Because of the importance of the s-parameter to characterize the device's performances and design the power amplifier, the theoretical simulation for the s-parameter is done in terms of the model of field-effect transistors with MATLAB. A power amplifier has been designed and implemented using PSpice, moreover, whose bandwidth is broadened by the negative feedback.As far as linearity and efficiency are concerned, several techniques and theoretical analyses on linearity are extensively demonstrated. Hybrid use of linear techniques and adaptation technologies in SDR are fully studied so that it can provides amplify with broadband, high efficiency and linearity. The paper presents anew scheme of an adaptive feedforward correction connected with a predistorter to amplify in SDR.At last, the trend of designing the PA in SDR under software control is forecasted. Therefore, the direction of the intending investigation is viewed, which is suitable for the future development of communications.