A Compact Superconducting Heterodyne Focal Plane Array Implemented With HPI (Hybrid Planar Integration) Scheme

Abstract

The article is concerned with the experimental evidence that proves technical feasibility of the hybrid planar integration (HPI) scheme that has been proposed to construct superconductor-insulator-superconductor (SIS) mixer focal plane arrays of unprecedented compactness. The scheme is characterized by the adoption of silicon membrane-based waveguide probes, which allows superconducting monolithic microwave integrated circuits to couple signal, and local oscillator (LO) from (computer numerical control)-machined waveguides through multiple paths. A 2 x 2 dual-polarization balanced SIS mixer array has been implemented with this scheme, and assessed in 125 - 163 GHz RF band. This compact array has demonstrated uniform LO distribution, and low crosstalk between pixels. The RF performance of component pixels has been confirmed to be little affected by the high-degree integration. The potential implementation of the HPI scheme at THz frequencies is also discussed.