Waveform Engineering at Gate Node of Class-J Power Amplifiers
Waveform Engineering at Gate Node of Class-J Power Amplifiers
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J 类功率放大器栅极节点的波形工程
DOI：
10.1109/tmtt.2017.2651814
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发表时间：
2017
影响因子：
4.3
通讯作者：
A. Medi
中科院分区：
文献类型：
--
作者：
A. Alizadeh;Milad Frounchi;A. Medi
本文研究了在晶体管的栅极节点形成正弦、半正弦(HS)、三角形、脉冲和降低导通角的电压波形时的J类工作模式。给出并比较了各输入信号的输出功率、最大功率附加效率(PAE)、大信号增益(LSG)和负载牵引等值线。结果表明，在J类功率放大器(PA)的栅极上施加HS电压，可以改善PA的PAE。然而，对于占空比为20%的脉冲输入，也可以观察到这种增强，但代价是输出功率和LSG降低。概念验证、两级J类功率放大器的设计和制造采用0.25-lt；直插式公式=“LaTeX”>；$\MU\Text{m}$<；/特数学/直插式AlGaAsInGaAsPHEMT工艺。原型PA基于第二级晶体管的HS栅极电压，第二级晶体管工作在J类模式。驱动器级也工作在J类模式，在其漏极节点提供HS电压，级间匹配网络被设计为将该波形传送到第二级晶体管的栅极。芯片尺寸为<；内联公式>；<；tex-ath notation=“LaTeX”&>$1.99\×1.24$<；/内联-公式&>mm</sup>，在0.92-1.4 GHz带宽上实现了26.6-27.2dBm的输出功率，≥为50%PAE。
In this paper, the class-J mode of operation is investigated when sinusoidal, half-sinusoidal (HS), triangle, pulse, and reduced conduction angle voltage waveforms are shaped at the gate node of the transistor. Output power, maximum power-added efficiency (PAE), large signal gain (LSG), and load–pull contours are presented and compared for each input signal. It is shown that PAE of a class-J power amplifier (PA) is improved when an HS voltage is realized at the gate node of the transistor. This enhancement can also be observed for a pulse input with 20% duty cycle, however, at the expense of reduced output power and LSG. A proof-of-concept, two-stage class-J PA is designed and fabricated in a 0.25-<inline-formula> <tex-math notation="LaTeX">$\mu \text{m}$ </tex-math></inline-formula> AlGaAs-InGaAs pHEMT technology. The prototype PA is based on an HS gate voltage for the second-stage transistor, which operates in class-J mode. The driver stage also works in class-J mode to provide an HS voltage at its drain node, and the interstage matching network is designed to convey this waveform to gate of the second-stage transistor. Chip dimensions are <inline-formula> <tex-math notation="LaTeX">$1.99\times1.24$ </tex-math></inline-formula> mm<sup>2</sup>, and 26.6–27.2-dBm output power with ≥50% PAE is achieved over the 0.92–1.4-GHz bandwidth.