Balanced superconductor-insulator-superconductor mixer on a 9~$\mu$m silicon membrane

TL;DR

This paper reports a novel balanced SIS mixer on a thin silicon membrane operating at 380-520 GHz with low noise temperatures and high noise suppression, advancing high-frequency receiver technology.

Contribution

It introduces a balanced SIS mixer on a 9 μm silicon membrane with state-of-the-art noise performance and integrated RF components on a single substrate.

Findings

Achieved minimum receiver noise temperature of 70 K.

Demonstrated noise suppression up to 18 dB.

Operated effectively within 440-495 GHz RF and 4-8 GHz IF bandwidth.

Abstract

We present a 380-520 GHz balanced superconductor-insulator-superconductor (SIS) mixer on a single silicon substrate. All radio-frequency (RF) circuit components are fabricated on a $9 \mu$m thick membrane. The intermediate frequency (IF) is separately amplified and combined. The balanced mixer chip, using Nb/Al/Al$_{2}$O$_{3}$/Nb SIS junctions, is mounted in a tellurium copper waveguide block at 4.2 K using Au beam lead contacts. We find uncorrected minimum receiver double-sideband noise temperatures of 70 K and a noise suppression of up to 18 dB, measured within a 440-495 GHz RF and a 4-8 GHz IF bandwidth, representing state-of-the-art device performance.