Series-connected array of superconductor-insulator-superconductor junctions in the 100-GHz band heterodyne mixer for FOREST on the Nobeyama 45-m telescope

Abstract

In this study, we designed and experimentally evaluated a series-connected array of superconductor-insulator-superconductor (SIS) junctions in the 100-GHz band mixer for the multi-beam receiver FOREST on the Nobeyama 45-m millimeter-wave telescope. The construction of the junction chip comprised a waveguide probe antenna, impedance matching circuit, SIS array junction, and choke filter, which were made from a superconducting niobium planar circuit on a quartz substrate. The multi-stage impedance matching circuit between the feed point and the SIS junction was designed as a capacitively loaded transmission line, and it comprised two sections with high (~90 Ohm) and low (~10 Ohm) characteristic impedance transmission lines. The structure of this tuning line was simple and easy to fabricate, and the feed impedance matched with the SIS junction in a wide frequency range. The signal coupling efficiency was more than 92% and the expected receiver noise temperature was approximately two times the quantum limit for 75-125 GHz based on quantum theory. The array junction devices with 3-6 connected junctions were fabricated and we measured their performance in terms of the receiver noise temperature and gain compression in the laboratory. We successfully developed an array junction device with a receiver noise temperature of ~15-30 K and confirmed that the improvement in the saturation power corresponded to the number of junctions. The newly developed array junction mixer was installed in the FOREST receiver and it successfully detected the 12CO (J = 1-0) molecular line toward IRC+10216 with the Nobeyama 45-m telescope.

arXiv comment10 pasges, 8 figures, Accepted for publication in PASJ

References in corpus (3)

• A New 100-GHz Band Front-End System with a Waveguide-Type Dual-Polarization Sideband-Separating SIS Receiver for the NRO 45-m Radio Telescope
• A New 100-GHz Band Two-Beam Sideband-Separating SIS Receiver for Z-Machine on the NRO 45-m Radio Telescope
• New 60-cm Radio Survey Telescope with the Sideband-Separating SIS Receiver for the 200 GHz Band

Cited by in corpus (7)

• New insights in the HII region G18.88-0.49: hub-filament system and accreting filaments
• FOREST Unbiased Galactic plane Imaging survey with the Nobeyama 45 m telescope (FUGIN). VI. Dense gas and mini-starbursts in the W43 giant molecular cloud complex
• Uncovering distinct environments in an extended physical system around the W33 complex
• Nobeyama 45 m Local Spur CO survey. I. Giant molecular filaments and cluster formation in the Vulpecula OB association
• Waveguide-Type Multiplexer for Multiline Observation of Atmospheric Molecules using Millimeter-Wave Spectroradiometer
• Ammonia mapping observations of the Galactic infrared bubble N49: Three NH${}_3$ clumps along the molecular filament
• Development of the new multi-beam receiver and telescope control system for NASCO