Linearization of High-Power Radio Frequency (RF) Amplifiers by Predistortion Method with Cubic Distortion Generation of MOSFET Transistors
Subject Areas : electrical and computer engineering
Mohamad Youness Ansarey Movahed
1
,
M. R. Motavalli Kasmaie
2
1 - Elec. Eng. Dept., Faculty of Engineering, University of Qom, Qom, Iran
2 - Elec. Eng. Dept., Faculty of Engineering, University of Qom, Qom, Iran
Keywords: Nonlinear high power amplifier, predistortion method, third and fifth order distortion, cubic distortion,
Abstract :
In this paper, the third-order (3IMD) and fifth-order (5IMD) distortion components of a high-power radio frequency nonlinear amplifier are reduced by the predistortion method and by generating cubic distortion using a MOSFET transistor. The predistortion method has many applications in linearizing high-power radio frequency amplifiers for telecommunication systems. The structure of this method is not complicated and can be easily used for linearizing nonlinear amplifiers. In this method, a distortion is placed as a complementary distortion at the input of a nonlinear amplifier to linearize the nonlinear amplifier by adding two distortions (i.e., the distortion caused by the nonlinear amplifier itself and the complementary distortion caused by another nonlinear element). Although the amount of linearization with this method is not very significant, this amount of linearization is sufficient for many telecommunication systems. The main advantage of this method is the simplicity of the circuit, high efficiency, and the ability to linearize over a relatively large frequency bandwidth. In this paper, the linearization value of the third and fifth order distortion signals of high power amplifiers is improved compared to previous similar works, and the results are shown using ADS software.