Multilevel Supply-Modulated Chireix Outphasing With Continuous Input Modulation
Multilevel Supply-Modulated Chireix Outphasing With Continuous Input Modulation
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DOI：
10.1109/tmtt.2017.2756038
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发表时间：
2017-12-01
影响因子：
4.3
通讯作者：
Popovic, Zoya
中科院分区：
文献类型：
--
作者：
Cappello, Tommaso;Barton, Taylor W.;Popovic, Zoya
本文介绍了具有调制信号的多级 (ML) Chireix 异相 (ML-CO) 功率放大器 (PA) 的动态特性。 ML-CO 技术结合了包络跟踪和异相架构的优点，通过高效的功率 DAC 调制器将电源调制限制在离散级别，并使用异相进行精细幅度控制。我们描述了一个实验测试台，它提供所需的相位和时间对齐的调制信号，以同时进行异相和电源调制。脉冲表征用于设计 ML 无记忆多项式 DPD。线性化 ML-CO GaN X 频段 MMIC PA 具有固定输入驱动电平，可实现 9.3dB 峰值平均功率比 (PAPR)、1.4MHz 和 11.3dB PAPR、9.7GHz 载波的 10MHz LTE 信号。对于这两个信号，当使用电源调制时，平均总功耗降低了两倍。提出了控制信号生成策略的研究，包括离散电源和连续输入调制的组合。简单的指数函数可跟踪 ML-CO PA 的最佳效率轨迹，从而使整体效率提高 9 个百分点至 27 个百分点。该控制策略应用于具有幅度整形和频率啁啾的雷达脉冲，与恒定电源操作相比，效率提高了高达11.8个百分点，频谱限制提高了29dB。
This paper presents a dynamic characterization of a multilevel (ML) Chireix outphasing (ML-CO) power amplifier (PA) with modulated signals. The ML-CO technique combines the advantages of envelope tracking and outphasing architectures by limiting the supply modulation to discrete levels with an efficient power-DAC modulator and using outphasing for fine amplitude control. We describe an experimental test bench that supplies the required phase-and time-aligned modulated signals for outphasing and supply modulation simultaneously. Pulsed characterization is used to design an ML memoryless polynomial DPD. The linearized ML-CO GaN X-band MMIC PA is demonstrated with fixed input drive levels for 9.3-dB peakto- average power ratio (PAPR), 1.4-MHz and 11.3-dB PAPR, 10-MHz LTE signals with a 9.7-GHz carrier. For both signals, the average total power consumption is reduced by a factor of two when supply modulation is used. An investigation of control signal generation strategies is presented, including combinations of discrete supply and continuous input modulation. A simple exponential function tracks the optimal efficiency trajectory of the ML-CO PA, enabling overall efficiency improvements within 9 and 27 percentage points. This control strategy is applied to radar pulses with amplitude shaping and frequency chirp, with the efficiency improvement of up to 11.8 percentage points compared with constant-supply operation, with 29-dB improvement in spectral confinement.