HTS Quad-band High-sensitivity Receiver for a 4.5-m Radio Telescope

This paper presents a high-Tc superconducting (HTS) quad-band high-sensitivity receiver for a 4.5-m radio telescope. The developed receiver consists of an HTS quad-band filter, a cryogenic low-noise amplifier, and a high-reliability compact cryocooler. The HTS filter allows passage of only protected radio astronomy bands (1.4, 1.6, 1.7, and 2.3 GHz) and attenuates radio frequency interference (RFI) by 30 dB or more. The quad-band filter comprises a tri-band filter and a band rejection filter (BRF). The BRF has narrow-band response for reducing 1.6 GHz RFI, in consideration of RFI from satellite phones allocated adjacent to this radio astronomy frequency. The HTS receiver operates at 77 K, its mass is 15 kg, and it can directly connect to the feed antenna. In-band noise at the receiver is about 0.40 dB, demonstrating its high sensitivity.