[16p-W8E_308-1~8] 11.4 Analog applications and their related technologies

1:45 PM - 2:00 PM JST(4:45 AM - 5:00 AM UTC)

[16p-W8E_308-2] Fabrication and evaluation of a 300 GHz band SIS mixer for the space VLBI

〇Yosuke Murayama¹, Yoshinori uzawa¹, Takatomi Kumagai¹, Wenlei Shan¹, Yasunori Fujii¹, Haoran Kang¹, Takeshi Sakai², Eugene Lauria³, Keara Carter⁴, Mareki Honma¹, Edward Tong⁴ (1.NAOJ, 2.UEC, 3.UArizona, 4.CfA)

Keywords:

SIS mixer,Millimeter-wave heterodyne receiver,Superconducting tunnel junctions

Highly sensitive millimeter-wave reception in space requires superconducting mixers operating near the quantum noise limit. In this study, we fabricated and characterized a 300-GHz-band Superconductor–Insulator–Superconductor (SIS) mixer with potential application to space very long baseline interferometry (VLBI) observations. An SIS mixer employing an aluminum oxide (AlO_x) tunnel barrier was fabricated, achieving a critical current density of 12 kA/cm². The noise performance was evaluated through intermediate-frequency (IF) spectral measurements at a local oscillator frequency of 285 GHz. As a result, a double-sideband noise temperature of 30 K was achieved over the 4–9 GHz IF band. This performance approaches approximately twice the quantum noise limit, demonstrating low-noise operation of SIS mixers in the 300-GHz band.