A compact HTS filter subsystem

Summary form only given, as follows. We describe a compact, long-life High-Temperature Superconducting (HTS) filter subsystem for mobile telecommunication base stations. This system consists mainly of a HTS filter and a low-noise amplifier (LNA), which are cooled by a Stirling pulse tube type cryocooler. The cooler is compact and has a service life of more than 5 years, theoretically, because its head has no moving parts. The 13-pole HTS filter, which as a 20 MHz bandwidth at 1.955 GHz, is made using a YBCO HTS thin film, and has a minimum insertion loss of less than 0.2 dB at 70 K. The HTS filter and LNA are packaged in a vacuum chamber, which can retain vacuum for more than 5 years operated under constant temperature-controlled conditions.