High-sensitivity HTS multi-channel receiver front-end for 900 MHz band mobile base station

This paper presents a high-sensitivity high-Tc superconducting (HTS) multi-channel receiver front-end for a 900 MHz band mobile base station. The front-end system has six input/output channels to correspond to a three-sector mobile base station. The front-end modules consist of a thermal insulation transmission line, a small HTS bandpass filter, a cryogenic low-noise amplifier and a high-reliability compact cryocooler. To realize a compact front-end system using a cryocooler, a low-loss thermal insulation transmission line is developed. The thermal insulation transmission line realizes an insertion loss of 0.08 dB and thermal conductivity 1/5 that of conventional thermal insulation semi-rigid coaxial cable. The characteristics of the developed HTS six-channel front-end system operated at 77 K include center frequency of 910 MHz, passband width of 15 MHz, and noise figure of 0.45 dB. The front-end system realized high sensitivity.