Comparing the performance of 850 GHz integrated bias-tee superconductor-insulator-superconductor (SIS) mixers with single- and parallel-junction tuner
Comparing the performance of 850 GHz integrated bias-tee superconductor-insulator-superconductor (SIS) mixers with single- and parallel-junction tuner
复制标题
比较 850 GHz 集成偏置 T 形超导体-绝缘体-超导体 (SIS) 混频器与单结和并联调谐器的性能
DOI：
10.1088/1361-6668/ac9d6e
复制
发表时间：
2022
影响因子：
3.6
通讯作者：
Tan B
中科院分区：
文献类型：
--
作者：
Tan B
我们提出并比较了两个850 GHz径向探头馈电超导体-绝缘体-超导体混频器的设计和性能，其中天线垂直于连接到多个耀斑角光滑壁喇叭的输入全高矩形波导的e面。这两种设计都是由0.5 μ m2的铌/氮化铝/铌-氮化隧道结组成，在氮化铌钛接地面上制作，并带有Al布线层。整个超导电路由40µm厚的石英衬底支撑。这两种设计的主要区别在于用于消除宽带性能的寄生结电容的方法。第一种设计利用两个相同的结与短传输线并联，将一个结的电容转换为另一个结的等效电感，通常称为双结调谐方案；而第二种设计采用端载方案，只有一个隧道结。我们发现这两种方法提供了相似的射频性能，接近双边带量子噪声温度的2倍，但双结设计更能适应制造公差。然而，端负载设计提供了更好的中频（IF）带宽性能，通过亚微米和高电流密度隧道结技术成为可能。改进的中频性能对于许多毫米和亚毫米天文台非常重要，例如未来升级的阿塔卡马大型毫米/亚毫米阵列接收机，以及即将到来的星载远红外任务。因此，我们得出结论，单结混频器设计是太赫兹应用的首选，只要制造误差可以在一定范围内最小化。
We present and compare the design and performance of two 850 GHz radial probe fed superconductor-insulator-superconductor mixers, where the antenna is aligned perpendicular to the E-Plane of the input full-height rectangular waveguide connected to a multiple flare-angles smooth-walled horn. Both designs are comprised of 0.5 µm 2 hybrid niobium/aluminium-nitride/niobium-nitride tunnel junction, fabricated on top of a niobium titanium nitride ground plane with an Al wiring layer. The entire superconducting circuit is supported with a 40 µm thick quartz substrate. The major difference between the two designs is the method used to cancel out the parasitic junction capacitance for broadband performance. The first design utilises two identical junctions connected in parallel with a short transmission line to convert the capacitance of one junction into the equivalent inductance of the other junction, commonly known as the twin-junction tuning scheme; whilst the second design employs an end-loaded scheme with only one tunnel junction. We found that both methods offer similar radio frequency performances, with close to 2× the double sideband quantum noise temperature, but the twin-junction design is more resilient to fabrication tolerances. However, the end-loaded design offers a much better intermediate frequency (IF) bandwidth performance, made possible by the sub-micron and high current density tunnel junction technology. The improved IF performance is important for many millimetre (mm) and sub-mm observatories, such as future upgrades of Atacama Large Millimetre/sub-mm Array receivers, as well as forthcoming space-borne far-infrared missions. Therefore, we conclude that the single-junction mixer design is the preferred option for THz applications, as long as the fabrication error can be minimised within a certain limit.