Continuous-Mode Hybrid Asymmetrical Load- Modulated Balanced Amplifier With Three-Way Modulation and Multi-Band Reconfigurability
Continuous-Mode Hybrid Asymmetrical Load- Modulated Balanced Amplifier With Three-Way Modulation and Multi-Band Reconfigurability
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DOI：
10.1109/tcsi.2021.3129166
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发表时间：
2022-03
期刊：
影响因子：
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通讯作者：
Yuchen Cao;Haifeng Lyu;Kenle Chen
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文献类型：
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作者：
Yuchen Cao;Haifeng Lyu;Kenle Chen
本文介绍了一种新颖的高阶负载调制功率放大器（PA）架构，即连续模式混合非对称负载调制平衡放大器（H-ALMBA）。 LMBA中平衡拓扑的两个子放大器（BA1和BA2）在与作为载波的控制放大器（CA）配合时被设置为具有不同阈值的峰值放大器，形成Doherty和ALMBA之间的混合负载调制行为。与标准 LMBA 相比，所提出的 H-ALMBA 通过适当的幅度控制和相位对齐，具有 CA、BA1 和 BA2 的三路负载调制。因此，这种新模式提供了扩展的功率回退范围和增强的回退效率，而不会像三路 Doherty PA 那样面临宽带设计的困难和复杂性。基于全面的理论推导和分析，所提出的 H-ALMBA 使用商用 GaN 晶体管和宽带正交耦合器进行设计和实现。此外，连续模式匹配应用于载波放大器，在功率回退时实现最大化宽带效率。这是连续模式和 ALMBA 首次结合使用，并取得了非常令人满意的结果，展现了宽带负载调制 PA 迄今为止报道的最高 10 dB OBO 漏极效率 (DE)。开发的原型通过实验证明了 1.7 美元 - 3.0 美元 GHz 的宽带宽。测量结果显示，在设计带宽内，峰值输出功率时的效率为 $63 - 81\%$，5dB OBO 的效率为 $51 - 62\%$，10dB OBO 的效率为 $50 - 66\%$。当由峰值平均功率比 (PAPR) 为 10.5 dB 的 20 MHz 长期演进 (LTE) 信号激励时，在整个带宽上以 32 dBm 左右的平均输出功率测得平均效率为 50 - 55\%$。
This article introduces a novel high-order load modulation power amplifier (PA) architecture, i.e., continuous-mode hybrid asymmetric load modulated balanced amplifier (H-ALMBA). The two sub-amplifiers (BA1 and BA2) of the balanced topology in an LMBA are set as peaking amplifiers with different thresholds when cooperating with the control amplifier (CA) as the carrier, forming a hybrid load modulation behavior between Doherty and ALMBA. Compared to standard LMBA, the proposed H-ALMBA has a three-way load modulation with CA, BA1 and BA2 through proper amplitude control and phase alignment. Thus, this new mode offers extended power back-off range and enhanced back-off efficiency without suffering from difficulty and complexity in wideband design as imposed on three-way Doherty PAs. Based on comprehensive theoretical derivation and analysis, the proposed H-ALMBA is designed and implemented using commercial GaN transistors and wideband quadrature couplers. Moreover, the continuous-mode matching is applied to the carrier amplifier achieving a maximized wideband efficiency at power back-off. This is the first time that continuous mode and ALMBA have been used in combination, and very satisfactory results have been achieved, exhibiting the highest 10-dB OBO drain efficiency (DE) ever reported for wideband load-modulation PAs. The developed prototype experimentally demonstrates wide bandwidth from $1.7 - 3.0$ GHz. The measurement exhibits an efficiency of $63 - 81\%$ at peak output power, $51 - 62\%$ for 5-dB OBO, and $50 - 66\%$ for 10-dB OBO within the design bandwidth. When stimulated by a 20-MHz long term evolution (LTE) signal with 10.5-dB peak to average power ratio (PAPR), a $50 - 55\%$ average efficiency is measured over the entire bandwidth at an average output power around 32 dBm.