Microwave properties and applications of high-T/sub C/ superconducting single-crystal films

• Published in: The Fifth International Kharkov Symposium on Physics and Engineering of Microwaves, Millimeter, and Submillimeter Waves (IEEE Cat. No.04EX828) Vol. 1; pp. 85 - 90 Vol.1
• Main Author: Pan, V.M.
• Format: Conference Proceeding
• Language: English
• Published: IEEE 2004
• Subjects: Anisotropic magnetoresistance; Band pass filters; Bandwidth; Buffer layers; Electrons; Kinetic theory; Microstrip filters; Microwave filters; Substrates; Yttrium barium copper oxide
• ISBN: 0780384113; 9780780384118
• DOI: 10.1109/MSMW.2004.1345793

The microstrip hairpin half-wave 9-pole bandpass YBCO filter for 1.7 GHz and bandwidth of about 80 MHz has been designed and made from double-sided YBCO film on 2" sapphire substrate with CeO/sub 2/ buffer layer. The losses in the designed filter with a pass band width of 80 MHz in a copper housing at 1.7 GHz were 0.7 dB at 77 K. The observed two-peak behavior of R/sub s/(T) dependence is a feature of the most perfect quasi-single-crystalline YBCO films, characterized by a smooth surface, low concentration of defects, large domain size and low-angle boundaries between them. In less perfect films the R/sub s/(T) dependence is monotonous. We suppose that the two-peak character of R/sub s/(T) observed for the first time is an intrinsic property and reveals the peculiarities of anisotropic electron pairing which can be properly described using the Boltzman kinetic equation for Bogolyubov quasiparticles.