一种高效率E-1/F类GaN HEMT射频功率放大器

A High Efficiency Class-E-1/F GaN HEMT RF Power Amplifier

使用GaN HEMT功率器件,设计了一款5G低频段的高效率E-1/F类射频功率放大器。为降低晶体管寄生参数及高次谐波对逆E类(E-1)功放开关特性和输出性能的不良影响,将具有寄生参数补偿的逆F类(F-1)谐波控制网络引入逆E类功放输出匹配电路中,实现了对二次谐波和三次谐波分别进行开路和短路处理,从而获得逆E类功放要求的良好开关特性。同时,得益于逆F类功放优良的谐波控制效果,改善了功放漏极电压和电流波形,大大降低其漏极峰值电压和电流,进而提升了功放的输出性能。实测结果表明,该功放在3.3~3.6 GHz的300 MHz有效工作带宽内的功率附加效率为59.1%~71.4%,最大漏极效率高达75.6%,输出功率在40.2~41.5dBm之间,增益平坦度在±1dB以内。最后利用20 MHz带宽的单载波LTE信号作为测试信号,基于广义记忆多项式数字预失真器对该功放进行线性化后,功放输出的邻信道功率比改善了近15 dB。

In this paper,a high efficiency Class-E-1/F RF power amplifier(PA)based on 5 G frequency band is proposed using GaN HEMT.In order to reduce the influence of the parasitic parameters and higher harmonics of the transistor on the switching performance and output characteristics of the Class-E-1 PA,the Class-F-1 PA harmonic control network with parasitic parameter compensation is introduced into the output power matching circuit of the Class-E-1 PA,to realize the open circuit and the short circuit processing for the second harmonic and the third harmonic respectively,so as to make the Class-E-1 PA possess good switching characteristics.Besides,due to the good performance of harmonic control of the Class-F-1 PA,the ideal waveform of the drain output current and voltage are realized which greatly reduced the PA’s drain current and voltage,and the output capability of the PA is improved greatly.The measured results show that in the effective operating bandwidth 300 MHz within 3.3~3.6 GHz,the Class-E-1/F PA has the power added efficiency(PAE)of 59.1%~71.4%,the maximum drain efficiency reaches 75.6%,the output power is among 40.2~41.5 dBm,and the gain flatness is within±1 dB.Finally,the amplifier is linearized by the generalized memory polynomial(GMP)digital pre-distorter(DPD)and tested by a 20 MHz bandwidth single-carrier LTE signal.The adjacent channel power ratio(ACPR)of the amplifier output is improved by nearly 15 dB.