Bandwidth Extension of Doherty Power Amplifier Using Complex Combining Load With Noninfinity Peaking Impedance
Bandwidth Extension of Doherty Power Amplifier Using Complex Combining Load With Noninfinity Peaking Impedance
复制标题
使用具有非无穷峰值阻抗的复杂组合负载的 Doherty 功率放大器的带宽扩展
DOI：
10.1109/tmtt.2018.2884415
复制
发表时间：
2019-02-01
影响因子：
4.3
通讯作者：
Li, Zhengzhou
中科院分区：
文献类型：
--
作者：
Yang, Zhenxing;Yao, Yao;Li, Zhengzhou
提出了一种采用非无穷大峰值阻抗复合合成负载的高效率Doherty功率放大器。通过应用CCL，可以在不同的工作频率下补偿饱和功率水平的载波放大器的负载阻抗。考虑到峰值功率放大器输出阻抗对载波功率放大器输出阻抗的影响，在整个工作频率范围内，详细分析了CCL的最佳非无穷大峰值输出阻抗。对输出功率和漏极效率的理论分析表明，CCL可以为DPA的带宽扩展提供一个新的自由度。在此基础上，基于GaN HEMT器件，设计并制作了工作在1.1- 2.4GHz（带宽74%）的改进型DPA。实验结果表明，在6dB输出下，回退漏效率为43.8%~ 54.9%，饱和漏效率为55.4%~ 68%。该放大器的饱和输出功率为43.3- 45.4dBm，增益为9.5- 11.1dB。当采用峰均功率比为6.5 dB的长期演进调制信号驱动时，DPA的邻道泄漏比优于−49 dBc，同时在数字预失真线性化后保持44%的DE。
In this paper, a high-efficiency Doherty power amplifier (DPA) using the complex combining load (CCL) with noninfinity peaking impedance for broadband operation is presented. By applying the CCL, the load impedance of the carrier amplifier at saturation power level can be compensated at different operation frequencies. Considering the influences of the output impedance of the peaking PA on the carrier PA, a detailed analysis of the optimal noninfinity peaking output impedance with the CCL is carried out on the whole operation frequency range. Theoretical analysis of the output power and drain efficiency (DE) reveals that the CCL can offer a new degree of freedom for extending the bandwidth of the DPA. Based on the proposed theory, a modified DPA working over the frequency band of 1.1–2.4 GHz (bandwidth of 74%) is designed and fabricated based on GaN HEMT devices. Experimental results exhibit 6-dB output back-off drain efficiencies of 43.8%–54.9% and saturated drain efficiencies of 55.4%–68% can be obtained. The saturated output power of the DPA is 43.3–45.4 dBm with a gain of 9.5–11.1 dB across the whole operation band. When driven with long-term evolution modulated signals with 6.5-dB peak-to-average power ratio, the DPA exhibits an adjacent channel leakage ratio better than −49 dBc while maintaining a DE of 44% after digital predistortion linearization.