The 2 GHz high temperature superconducting receiver equipment for mobile communications

Abstract

An ultra low noise and highly selective, experimental 2 GHz band cryogenic receiver front end (CRFE) has been newly developed for mobile communication base stations. It utilizes a high- Q superconducting filter, a very low noise cryogenic amplifier, and a highly reliable cooler that is very compact. The equivalent noise temperature ( T eq) of the CRFE is less than 50 K (0.69 dB of NF). According to current device data, T eq of normal temperature front ends in the 2 GHz band is typically 300 K (3 dB of NF). Thus, the improvement in sensitivity on mobile communication base station reception is estimated at 250 K (2.31 dB). If the CRFEs apply to W-CDMA base station receptions instead of normal temperature front ends, it is impossible to expand the coverage of a base station by about 70%. Alternatively, the capacity in W-CDMA system is able to increase by 10–160%. Furthermore, the transmission power of the user equipment can be reduced in proportion to the NF improvement.