| In recent years, with the rapid development of the third generation of wireless communication technology, wireless communication business volume rapid growth of mobile phones, people are generally satisfied with the rate of data transmission, in the pursuit of high-speed transfer rate while also taking into account the efficiency of the transmission and power consumption is the focus of current research.Now the third generation WCDMA communication system using the communication system is a multi-carrier modulation technique, the envelope variation of the multi-carrier modulation technique is relatively large, resulting in peak-average power ratio of the transmitted signal will be large and therefore require a linear power amplifier there is a relatively large linear region.Although the method of power back-off approach can effectively avoid signal distortion, but low efficiency of this method, the resulting energy waste.The digital predistortion power amplifier technology into being, proven, can be very effective to improve the power amplifier linear region amplification problems.At the same time, the structure of the Doherty type is relatively simple circuit model, the base station and repeater Doherty amplifier for the digital high-efficiency power output needs has become a research focus.In this paper, the structure of Doherty power amplifier is the main object of study, analysis of the basic ways of working Doherty power amplifier performance requirements according to Digital Repeater WCDMA power amplifier to choose, after referring to digital repeater indicators and Freescale provides the data model components, and ultimately determine the use of two Freescale’s LDMOS type MRF6S21140H tube, respectively, as the primary and secondary power amplifier power amplifier using ADS2008U2simulation software, simulation of structural Doherty power amplifier, and to be optimized, be tested and improved.The main contents are as follows:the use of ADS simulation platform MRF6S21140H this LDMOS the DC simulation analysis; design source and load-pull circuit network; design bias circuit and matching network; designed load modulation network; Doherty power amplifier design good simulation test to determine its performance. |
