2-GHz band cryogenic receiver front end for mobile communication base station systems

An ultra low-noise and highly selective, experimental 2-GHz band cryogenic receiver front end (CRFE) has been newly developed for cellular base statio ns. It utilizes a high-Q superconducting filter, a very low noise cryogenic amplifier, and a highly reliable cooler that is very compact. Fundamental design of the CRFE is investigated. First, the equivalent noise temperature of the CRFE and the effect of improving CRFE sensitivity on base station r eception are discussed. Next, essential technologies and fundamental charac teristics of each component are described. Finally, influence of antenna no ise, such as ground noise and man-made noise, is estimated through field te sts both in urban and suburban areas.