1-D Reconfigurable Pseudo-Doherty Load Modulated Balanced Amplifier With Intrinsic VSWR Resilience Across Wide Bandwidth
1-D Reconfigurable Pseudo-Doherty Load Modulated Balanced Amplifier With Intrinsic VSWR Resilience Across Wide Bandwidth
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DOI：
10.1109/tmtt.2023.3239399
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发表时间：
2023-06
影响因子：
4.3
通讯作者：
Jiachen Guo;Yuchen Cao;Kenle Chen
中科院分区：
文献类型：
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作者：
Jiachen Guo;Yuchen Cao;Kenle Chen
通过一维重构，提出了一种具有负载失配容限的宽带伪Doherty负载调制平衡放大器(PD-LMBA)。从理论上揭示了当PD-LMBA中的控制放大器(CA，作为载波)被驱动到饱和时，它被赋予了电流源(CS)和电压源(VS)的对偶性，这使得BA(AS峰值化)在负载不匹配的情况下，对于两个子放大器(BA1和BA2)具有互补的负载调制轨迹。因此，PD-LMBA中的BA继承了通用正交平衡放大器的固有负载不敏感度。同时，CA的饱和功率只需重新配置直流偏置电压($V{\mathm{DD，CA}}$)即可保持，该电压仅取决于负载阻抗的实部$\mathm(Z_{\mathm{L}})$。因此，功率放大器重新配置和负载检测的自由度(理想情况下)被最小化到一维，并且整个PD-LMBA可以针对任意负载失配保持几乎恒定的效率曲线。理论分析通过仿真电路模型得到了很好的验证，用GaN晶体管和宽带正交混合电路设计的原型进一步实验验证了理论分析的正确性。作为概念验证，制作的PD-LMBA电路在匹配负载下获得了最先进的测量性能，带宽为1.7-2.9 GHz，峰值功率为39-43 dBm时的漏极效率为65%-77%，10-dB输出回退(OBO)时的效率为55%-71%。更重要的是，样机还通过一维重构在2：1驻波比下的1.7、2.1和2.5 GHz三个典型的带内频率下显示了良好的失配恢复能力。具体地说，在整个2：1 VSWR循环中，峰值功率下的最大漏极效率从51.9%到72.8%，在10分贝的回退时，效率高达65.4%。还执行了使用LTE信号的调制评估，其中1-D可重构PD-LMBA在负载失配时表现出极佳的平均效率，其积极地优于最先进的技术。
This article presents the first-ever wideband pseudo-Doherty load-modulated balanced amplifier (PD-LMBA) with load-mismatch tolerance through 1-D reconfiguration. It is theoretically unveiled that when the control amplifier (CA, as a carrier) in PD-LMBA is driven to its saturation, it is endowed with a duality between the current source (CS) and voltage source (VS), which makes the BA (as peaking) have complementary load-modulation trajectories for the two sub-amplifiers (BA1 and BA2) under load mismatch. As a result, the BA in PD-LMBA inherits the intrinsic load insensitivity from the generic quadrature-balanced amplifier. Meanwhile, the saturation power of CA can be maintained by only reconfiguring the dc bias voltage ( $V_{\mathrm {DD,CA}}$ ) that solely depends on the real part of load impedance, real $\mathrm (Z_{\mathrm {L}})$ . As such, the degree of freedom for PA reconfiguration and load sensing (ideally) is minimized to 1-D, and the entire PD-LMBA can maintain a nearly constant efficiency profile against arbitrary load mismatch. The theoretical analysis is well verified using emulated circuit model, and it is further experimentally validated by a prototype designed with GaN transistors and wideband quadrature hybrids. As a proof of concept, the fabricated PD-LMBA circuit achieves state-of-the-art performance in measurement at matched load with 1.7–2.9 GHz of bandwidth, 65%–77% of drain efficiency at peak power of 39–43 dBm, and 55%–71% of efficiency at 10-dB output back-off (OBO). More importantly, the prototype also experimentally exhibits excellent mismatch resilience through 1-D reconfiguration, which is demonstrated at three representative in-band frequencies of 1.7, 2.1 and 2.5 GHz at 2:1 VSWR. Specifically, a maximum drain efficiency from 51.9% to 72.8% at peak power is achieved over the entire 2:1 VSWR circle, and an efficiency up to 65.4% is measured at 10-dB back-off. Modulated evaluation using an LTE signal is also performed, in which the 1-D reconfigurable PD-LMBA exhibits an excellent average efficiency at load mismatch that aggressively outperforms the state-of-the-art.