Balanced superconductor–insulator–superconductor mixer on a9 µm silicon membrane

Abstract

We present a 380–520 GHz balanced superconductor–insulator–superconductor (SIS) mixer ona single silicon substrate. All radio-frequency (RF) circuit components are fabricated on a9 µm thickmembrane. The intermediate frequency (IF) is separately amplified and combined. The balanced mixer chip,using Nb/Al/Al2O3/Nb SIS junctions, is mounted in a tellurium copper waveguide block at 4.2 K using Au beamlead contacts. We find uncorrected minimum receiver double-sideband noise temperaturesof 70 K and a noise suppression of up to 18 dB, measured within a 440–495 GHz RFand a 4–8 GHz IF bandwidth, representing state-of-the-art device performance.