GaN HEMT非线性输出电容寄生参数研究

分析了GaN（氮化镓）HEMT（高电子迁移率晶体管）非线性输出电容寄生参数Cout与功率放大器效率的关系。通过建立非线性电路模型分析得出，Cout与外部合适的匹配电路结合能产生类似电压半正弦波，电流方波的最优效率波形。选用GaN HEMT 器件设计S频段射频功率放大器,实测结果显示该放大器最高漏极效率（DE）为81.7%，功率附加效率（PAE）78.56%，功率为41.16dBm，在100M带宽内PAE也可达74.49%以上，并且结构简单。实测结果验证了原理分析的可靠性。

Study of Parasitic Nonlinear Output Capacitor of GaN HEMT

The relationship between parasitic nonlinear output capacitor Cout of GaN HEMT and efficiency is studied. Through the analysis of established nonlinear circuit model, results showed that combined with proper external matching circuit, Cout generates a quasi-rectangular current waveform and a quasi-half-sinusoidal voltage waveform, which are the most efficient waveforms. A highly efficient amplifier based on the principle is designed by using a Cree GaN HEMT device at S band. It provides a drain efficiency of 81.7% and a power-added efficiency of 78.56% at a saturated power of 41.16dBm,in addition, the PAE is higher than 74.49% in 100 MHz and topology is simple. Results prove the principle analysis is reliable.