Proof-of-Concept Experiment on a Wideband Microwave Gyrator with Two Superconductor– Insulator–Superconductor-Based Mixers

This article reports a proof-of-concept experiment on a wideband gyrator to realize an on-chip isolator or circulator. We propose a novel configuration of the gyrator composed of two superconductor–insulator–superconductor (SIS) mixers and two phase-delay circuits to downsize the gyrator and extend its operating frequency bandwidth. The operating frequency bandwidth and transmission characteristics that facilitate gyrator operations are investigated using existing waveguide SIS mixers. In addition, sideband cancellation, which considerably affects the transmission characteristics, is discussed. Although a 6 dB attenuator was inserted between the SIS mixers in this experiment, the average magnitude of
S
₂₁
and
S
₁₂
of the gyrator was found to be approximately −3 dB in the range of 0.01–5.00 GHz. In addition, the phase difference between
S
₂₁
and
S
₁₂
is 180 ± 10° within 0.10–5.00 GHz, indicating the operating of this configuration as a gyrator.