High-temperature superconductor-films microstrip band-pass filters for extreme working conditions

The microwave microstrip band-pass filters (BPF) for 1.7 GHz manufactured on the basis of normal metal (Cu) thin films, Au/YBCO bilayer films and pure YBCO thin films are investigated. Features of the BPF-construction on the basis of YBCO films are described. The designed high-temperature superconductor (HTS) BPF has electrodynamics characteristics (passband-loss, steepness of transition area from the pass-band to the stop-band etc.), which are inaccessible for normal metal film filters. The influence of moisture, storage in real atmosphere, temperature shocks on electrodynamic characteristics of the microwave HTS BPF with a narrow passband has been investigated. The characteristics of the designed HTS BPF in the hermetic housing were stable after 5 cycles of rapid cooling and heating (300 K darr 77 K uarr 300 K) and more than a year of usage. The designed construction of hermetic housings ensures safety of YBCO films in microwave devices for extreme operation regimes in satellite and cellular communication systems.