Fabrication and evaluation of high temperature superconducting thin films for filter applications

摘要

YBa{sub}2Cu{sub}3O{sub}y(YBCO)/CeO{sub}2 thin films were deposited on r-, c-, and a-plane sapphire substrates(r-, c-, a-Al{sub}2O{sub}3). The YBCO films on the a-Al{sub}2O{sub}3 showed c-axis orientation and a critical temperature T{sub}c of 88.6 K which is nearly the same as that on the r-Al{sub}2O{sub}3. Etching characteristics of the YBCO thin films by an ECR etching system were investigated. The etching rate on the area of 20 mm in diameter was approximately uniform, and its difference of the rate was below 4.3%. Duplexer was designed using 3- and 5-pole Chebychev-type band pass filter (BPF). Sharper skirt characteristic and better duplexer distribute-function could be got as increased the pole of Chebychev-type BPF, through simulations.