Design And Research Of High Efficiency RF Power Amplifiers

RF power amplifiers are widely used in RF/microwave communications. It is in the final stage of the transmitter. Its performance of the entire system has an important impact. At present, with large output power, high efficiency, high linearity RF power amplifier has become the focus of research. This paper focuses on how to improve the efficiency of the RF power amplifier to study for class AB, class E and Doherty technology.Based on the analysis of the RF power amplifier design method, we design work on1.9GHz AB power amplifier based on a LDMOS power transistor MW6S004N, the use of source and load-pull method to design the amplifier input and output matching networks on the ADS platform,. wei select the harmonic balance method collaborative schematic and layout simulation, the results shows that:PldB=35.935dBm, PAE=47.927, Gain=17.935; the class AB power amplifier efficiency did not meet our expectations.This paper use LDMOS power transistor MRF27015designed a Doherty power amplifier to improve efficiency by adding the output of the delay line, to improve the Doherty amplifier output impedance, so that the output impedance of the power amplifier closer to the theoretical value, thus so that efficiency is improved simulation results show that:when the Pin=28dBm, PAE=55%, P1dB close to45dBm. Due to limitations in the performance LDMOS power transistor, so that the linearity of the Doherty amplifier is not ideal; In order to improve efficiency and the harmonic suppression at the same time, this paper designed GaN class E power amplifier which use a distributed structure. Simulation results show that:the Pin=23dBm, PAE=77%, and P1dB close to43dBm, harmonic suppression of more than-45dB. This indicates that the amplifier has a good effect of suppressing harmonics and significant improvement in efficiency.The results of this paper to promote the application of high efficiency RF power amplifier has an important reference value.