High Power, High Efficiency Linear Power Amplifier Technology

With the development of the new communication and modulation technique, there are more requests including PAR (peak average ratio), PAE (power added efficience), linearity for radio frequence equipment used in these systems, such as base station, repeator station. As the most important part of these equipments, PA (power amplifier) is the key way to meet the requests. Whereas, according to the original PA theory, it is very difficult to balence the linearity and PAE when the input-signal with a high PAR at the same time. How to solve this problem has become more and more important in the RF engineering field.In this paper, based on a sufficient study on various efficiency enhancement techniques, one kind of Doherty amplifier with uneven input drive and low memory effection was presented which is used in the design and implemention of a 30W high efficience performance power amplifier applicated in the W-CDMA base station. The simulation results show that the PAE of the Doherty PA is over 32% with 45dBm output level.Further more, according to combining the Doherty PA and RF preditortion technique, a better way was proposed to improve the linearity performance, which meets the request for linearity of the PA with the high efficience performance already achicved. At last, an adaptive controlling module applicated in the RF predistortion technique was presented. According to experiment, a predistortion detecting module which is one of the two key parts in the daptive controlling module was validated. The measurement results show the detecting module is capable of detecting W-CDMA distortion signal in different bands with the input power rang from -20dBm to 5dBm.