Design and analysis of the NRC Q-band receiver for ngVLA Band-5

Abstract

The radio instrumentation team (RIT) at NRC’s (National Research Council Canada) Herzberg astronomy and astrophysics research center (HAA) is currently developing a dual-linear polarization, single-feed Q-band cryogenic radio astronomy receiver to develop and demonstrate important technologies needed for front-end development for the next generation very large array (ngVLA) project lead by the National Radio Astronomy Observatory (NRAO). The specific target is the ngVLA band-5 receiver, which covers the frequency range 30.5–50.5 GHz. It also serves as a technology demonstrator for component development for ngVLA bands-3, 4, and 6. The Q-band receiver system is designed to achieve a receiver noise temperature of less than 20 K over 70% of the bandwidth and better than 24 K over the complete operating bandwidth, and is compliant with the current ngVLA Band-5 receiver requirement. The receiver system consists of a cryostat with a cooled feed horn, a turnstile OMT (orthomode transducer) plus two noise couplers for calibration, two cryogenic mHEMT low noise amplifiers with noise temperature lower than 14 K, IR filters, and a vacuum window for low-loss transmission of electromagnetic fields into the cryostat.