To achieve the low noise and wide bandwidth required for millimeter wavelength astronomy applications, superconductor-insulator-superconductor (SIS) mixer based receiver systems have typically been used. This paper investigates the performance of high electron mobility transistor (HEMT) based low noise amplifiers (LNAs) as an alternative approach for systems operating in the 125 - 211 GHz frequency range. A four-stage, common-source, unconditionally stable monolithic microwave integrated circuit (MMIC) design is presented using the state-of-the-art 35 nm indium phosphide HEMT process from Northrop Grumman Corporation. The simulated MMIC achieves noise temperature (Te) lower than 58 K across the operational bandwidth, with average Te of 38.8 K (corresponding to less than 5 times the quantum limit (hf/k) at 170 GHz) and forward transmission of 20.5 +/- 0.85 dB. Input and output reflection coefficients are better than -6 and -12 dB, respectively, across the desired bandwidth. To the authors knowledge, no LNA currently operates across the entirety of this frequency range. Successful fabrication and implementation of this LNA would challenge the dominance SIS mixers have on sub-THz receivers.

中文翻译：

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用于射电天文的 125 - 211 GHz 低噪声 MMIC 放大器设计

为了实现毫米波天文学应用所需的低噪声和宽带宽，通常使用基于超导体-绝缘体-超导体 (SIS) 混频器的接收器系统。本文研究了基于高电子迁移率晶体管 (HEMT) 的低噪声放大器 (LNA) 的性能，作为在 125 - 211 GHz 频率范围内运行的系统的替代方法。使用 Northrop Grumman Corporation 最先进的 35 nm 磷化铟 HEMT 工艺展示了一种四级、共源、无条件稳定的单片微波集成电路 (MMIC) 设计。模拟的 MMIC 在整个操作带宽上实现了低于 58 K 的噪声温度 (Te)，平均 Te 为 38.8 K（对应于小于 170 GHz 时量子极限 (hf/k) 的 5 倍）和 20 的前向传输。5 +/- 0.85 分贝。在所需带宽上，输入和输出反射系数分别优于 -6 和 -12 dB。据作者所知，目前没有 LNA 在整个频率范围内运行。该 LNA 的成功制造和实施将挑战 SIS 混频器在亚太赫兹接收器上的主导地位。