Analysis of the third harmonic for class-F power amplifiers with an Ⅰ–Ⅴ knee effect  

作　　者：赵博超 卢阳 魏家行 董梁 王毅 曹梦逸 马晓华 郝跃 

机构地区：[1]Key Laboratory of Wide Band-Gap Semiconductor Materials and Devices, School of Microelectronics, Xidian University [2]School of Advanced Materials and Nanotechnology, Xidian University

出　　处：《Chinese Physics B》2015年第5期592-596,共5页中国物理B（英文版）

摘　　要：The appearance of third-generation semiconductors represented by gallium nitride （GaN） material greatly improves the output power of a power amplifier （PA）, but the efficiency of the PA needs to be further improved. The Class-F PA reduces the overlap of drain voltage and current by tuning harmonic impedance so that high efficiency is achieved. This paper begins with the principle of class-F PA, regards the third harmonic voltage as an independent variable, analyzes the influence of the third harmonic on fundamental, and points out how drain efficiency and output power vary with the third harmonic voltage with an I-V knee effect. Finally, the best third harmonic impedance is found mathematically. We compare our results with the Loadpull technique in advanced design system environment and conclude that an optimized third harmonic impedance is open in an ideal case, while it is not at an open point with the I-V knee effect, and the drain efficiency with optimized third harmonic impedance is 4% higher than that with the third harmonic open.The appearance of third-generation semiconductors represented by gallium nitride （GaN） material greatly improves the output power of a power amplifier （PA）, but the efficiency of the PA needs to be further improved. The Class-F PA reduces the overlap of drain voltage and current by tuning harmonic impedance so that high efficiency is achieved. This paper begins with the principle of class-F PA, regards the third harmonic voltage as an independent variable, analyzes the influence of the third harmonic on fundamental, and points out how drain efficiency and output power vary with the third harmonic voltage with an I-V knee effect. Finally, the best third harmonic impedance is found mathematically. We compare our results with the Loadpull technique in advanced design system environment and conclude that an optimized third harmonic impedance is open in an ideal case, while it is not at an open point with the I-V knee effect, and the drain efficiency with optimized third harmonic impedance is 4% higher than that with the third harmonic open.

关 键 词：class-F power amplifier third harmonic I-V knee effect Loadpull technique 

分 类 号：TN722[电子电信—电路与系统]