Design and Linearization of Concurrent Dual-Band Doherty Power Amplifier With Frequency-Dependent Power Ranges
Design and Linearization of Concurrent Dual-Band Doherty Power Amplifier With Frequency-Dependent Power Ranges
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DOI：
10.1109/tmtt.2011.2164089
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发表时间：
2011-09
影响因子：
4.3
通讯作者：
Wen-hua Chen;S. Bassam;Xiang Li;Yucheng Liu;K. Rawat;M. Helaoui;F. Ghannouchi;Zhenghe Feng
中科院分区：
文献类型：
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作者：
Wen-hua Chen;S. Bassam;Xiang Li;Yucheng Liu;K. Rawat;M. Helaoui;F. Ghannouchi;Zhenghe Feng
提出了一种具有频率相关回退功率范围的并行双频Doherty功率放大器的设计方法。基于双频T形网络和耦合线网络，研制了Doherty PA拓扑结构所需的不同双频元件，包括3 dB分支线耦合器、偏置线和四分之一波长Transformer。实现了两个具有平衡和不平衡回退功率范围模式的原型，以验证其可行性。连续波信号测试结果表明，所提出的双频PA成功地实现了33%和30%的功率增加效率从饱和输出功率在880和1960 MHz，分别在6 dB回退点。为了满足线性度要求，PA的非线性行为的特点是使用数字多音信号，其中分类的并发双频PA的失真为互调和交叉调制。最后，采用二维数字预失真技术对双频段功放的非线性进行补偿。两个双音信号被施加到双频段进行线性化，实验结果表明，该技术实现了优于19.1和24.6 dB的改善，在双频段的互调和交叉调制，分别。
A design methodology for a concurrent dual-band Doherty power amplifier (PA) with frequency-dependent backoff power ranges is presented in this paper. Based on a dual-band T-shaped network and a coupled line network, different dual-band components needed in Doherty PA topology, including a 3-dB branch-line coupler, an offset line, and a quarter-wavelength transformer, are developed. Two prototypes with balanced and imbalanced backoff power range modes are implemented to verify the feasibility. Continuous wave signal test results show that the proposed dual-band PA successfully achieves a power-added efficiency of 33% and 30% at the 6-dB backoff point from the saturated output power at 880 and 1960 MHz, respectively. To meet linearity requirements, the PA nonlinear behavior is characterized by using digital multitone signals, which categorize the distortions of a concurrent dual-band PA into intermodulation and cross-modulation. Finally, a 2-D digital predistortion technique is used to compensate for the nonlinearity of PA in dual bands. Two two-tone signals are applied to the dual bands for linearization, and the experimental results show that this technique achieves improvements of better than 19.1 and 24.6 dB for the intermodulation and cross-modulation in the dual bands, respectively.