Design Of 5G Medium Band Broadband High Efficiency Power Amplifier

With the continuous evolution and development of mobile communication technology,the requirements for wireless communication equipment are constantly strengthened.As the core part of the transmitter,the performance of RF power amplifier plays a decisive role in the performance indicators of the transmitter.In recent generations of wireless communication systems,there are more and more modulation methods of PAPR.Among many power amplifiers,the efficiency advantage of Doherty power amplifier after backoff is valued by many researchers.Based on the development trend of technology in recent years and the evolution direction of power amplifier in the future,a broadband efficient Doherty power amplifier working in 5G band is developed:Firstly,this paper describes the development process of mobile communication and the urgent technical demand for Doherty power amplifier,reviews the research progress of Doherty power amplifier in recent 10-20 years,and summarizes the areas that still need to be improved,including performance improvement,expansion in dynamic range,broadbandization and so on.Then,it introduces the basic theory of power amplifier,including the working principle,amplifier classification and related technical indicators,and briefly describes the traditional architecture and limitations of Doherty power amplifier.Based on S-parameter analysis theory,stability design method and load traction technology,Doherty’s basic design program was studied.Finally,CREE company’s CGH40010 F transistor was selected based on the design indicator,and a Doherty power amplifier working in3.2GHz-3.7GHz frequency band was designed with ADS artificial tool.The design work included transistor selection,power divider design,main and auxiliary power amplifier design,and post stage circuit matching design.After that,the overall artificial optimization(including layout joint artificial design)was carried out.After the design was completed,the circuit board was made,assembled and tested.In the final test results,the output power reacheed 43 dbm at saturation state,the gain was over 10 dB,and the drain efficiency was around 65%.After 6dB backoff,the output power reacheed 37 dbm,the gain was more than 12.5db,and the drain efficiency was about 45%,which basically meets the design requirements.