A common‐drain power amplifier (PA) for envelope tracking systems is presented. In envelope tracking, the main PA operates mostly in compression and the power supply rejection ratio (PSRR) is not high. Furthermore, the output noise of the supply modulator can be mixed with the RF signal and generates out‐of‐band emissions. In this article, instead of using a common‐source topology, the PSRR of the envelope tracking PA is inherently improved by utilizing a common‐drain topology. A comprehensive analysis shows that the common‐drain topology is less sensitive to the supply noise, as compared to the conventional common‐source topology. The proposed common‐drain PA is implemented using a discrete LDMOS PD20010‐E RF transistor. Measurement results show that the PSRR of the proposed common‐drain PA is improved by up to 7 dB as compared to that of the common‐source PA. For a two‐tone input with 10 MHz bandwidth at the center frequency of 700 MHz, the power added efficiency (PAE) and IM3 of the envelope tracking common‐drain PA are 20% and − 28 dBc, respectively, at an average output power of 33.4 dBm. The amplifier also shows a 12.4 dB power gain. Moreover, by utilizing the envelope tracking, the PAE is improved by more than 5%.

中文翻译：

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使用共漏放大器拓扑分析和改善包络跟踪功率放大器中的PSRR

提出了一种用于包络跟踪系统的共漏极功率放大器（PA）。在包络跟踪中，主功率放大器主要在压缩状态下工作，电源抑制比（PSRR）不高。此外，电源调​​制器的输出噪声可与RF信号混合并产生带外发射。在本文中，不使用共源拓扑，而是利用共漏拓扑从本质上改善了包络跟踪PA的PSRR。全面的分析表明，与传统的共源拓扑相比，共漏拓扑对电源噪声的敏感性较低。拟议的共漏极功率放大器使用分立的LDMOS PD20010-E RF晶体管实现。测量结果表明，与共源功率放大器相比，建议的共漏极功率放大器的PSRR最高可提高7 dB。对于中心频率为700 MHz且带宽为10 MHz的双音输入，在平均输出功率下，包络跟踪共漏PA的功率附加效率（PAE）和IM3分别为20％和− 28 dBc 33.4 dBm。放大器还显示了12.4 dB的功率增益。此外，通过利用包络跟踪，PAE改善了5％以上。