HTS L-S band High-sensitivity Receiver for a 20-m Cassegrain Radio Telescope

This paper presents a high-Tc superconducting (HTS) quad-band high-sensitivity receiver for a 20-m Cassegrain 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, and it can connect to the 4×4 array feed antenna. In-band noise factor at the receiver is about 0.60 dB, demonstrating its high sensitivity.