Pseudo-Doherty Load-Modulated Balanced Amplifier With Wide Bandwidth and Extended Power Back-Off Range
Pseudo-Doherty Load-Modulated Balanced Amplifier With Wide Bandwidth and Extended Power Back-Off Range
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DOI：
10.1109/tmtt.2020.2983925
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发表时间：
2020-04
影响因子：
4.3
通讯作者：
Yuchen Cao;Kenle Chen
中科院分区：
文献类型：
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作者：
Yuchen Cao;Kenle Chen
本文提出了一种新颖的负载调制平衡放大器（LMBA）架构，具有不同于任何现有 LMBA 和 Doherty 功率放大器（DPA）的独特负载调制特性，被称为伪 Doherty LMBA（PD-LMBA）。基于控制放大器（载波）和平衡放大器（峰值）的特殊组合以及适当的相位和幅度控制，PD-LMBA 可以实现最佳负载调制行为，从而在扩展的功率回退范围内实现效率最大化。更重要的是，在给定频率下仅通过静态设置相位偏移即可实现效率优化，这大大简化了相位控制的复杂性。此外，PD-LMBA中载波放大器和峰值放大器的合作是完全解耦的，从而消除了基于Doherty的有源负载调制的基本带宽障碍。根据这些发现的理论证明，使用 GaN 技术物理开发了宽带射频输入 PD-LMBA 进行实验演示。该原型在 1.5 至 2.7 GHz 范围内实现了高效性能，例如，在 42.5 dBm 峰值功率下效率为 58%–72%，在 10 dB 输出回退 (OBO) 下效率为 47%–58%。当受到峰均功率比 (PAPR) 为 9.5dB 的 10MHz 长期演进 (LTE) 信号刺激时，所开发的 PD-LMBA 在整个带宽上实现了 44%–53% 的效率，平均输出功率约为 33dBm。
This article presents a novel architecture of load-modulated balanced amplifier (LMBA) with a unique load-modulation characteristic different from any existing LMBAs and Doherty power amplifiers (DPAs), which is named pseudo-Doherty LMBA (PD-LMBA). Based on a special combination of control amplifier (carrier) and balanced amplifier (peaking) together with proper phase and amplitude controls, an optimal load-modulation behavior can be achieved for PD-LMBA, leading to maximized efficiency over extended power back-off range. More importantly, the efficiency optimization can be achieved with only a static setting of phase offset at a given frequency, which greatly simplifies the complexity for phase control. Furthermore, the cooperations of the carrier and peaking amplifiers in PD-LMBA are fully decoupled, thus lifting the fundamental bandwidth barrier imposed on the Doherty-based active load modulation. Upon theoretical proof of these discoveries, a wideband RF-input PD-LMBA is physically developed using the GaN technology for experimental demonstration. The prototype achieves a highly efficient performance from 1.5 to 2.7 GHz, e.g., 58%–72% of efficiency at 42.5-dBm peak power and 47%–58% at 10-dB output back-off (OBO). When stimulated by a 10-MHz long term evolution (LTE) signal with a 9.5-dB peak-to-average power ratio (PAPR), the developed PD-LMBA achieves an efficiency of 44%–53% over the entire bandwidth at an average output power of around 33 dBm.