High-T/sub c/-superconductor-sapphire microwave resonator with extremely high Q-values up to 90 K

A theoretical analysis was performed for an extremely high-Q resonator formed by a sapphire rod sandwiched by a pair of high-T/sub c/ superconductor (HTS) films. A number of these HTS-sapphire-HTS resonators at C-band and Ka-band were designed, fabricated, and tested. At 5.552 GHz, Q/sub 0/ reached 2*10/sup 6/ at 90 K, 3*10/sup 6/ at 80 K and 1.4*10/sup 7/ at 4.2 K with circulating power up to 500 kW. Formulas for calculating the resonant frequency and Q-value derived from the theoretical analysis were verified by experimental data with good agreement. Three different thin-film HTS materials-Tl/sub 2/Ba/sub 2/CaCu/sub 2/O/sub 8/, YBa/sub 2/Cu/sub 3/O/sub 7- delta / and Tl/sub 0.5/Pb/sub 0.5/Sr/sub 2/CaCu/sub 2/O/sub 7/-were tested. The sensitivity of the high Q-value and the parasitic coupling to the case modes are discussed. Applications such as frequency stabilized oscillators, filters, and HTS film characterization are described. >

[1]  P. Guillon,et al.  Dielectric resonators , 1988, Proceedings of the 42nd Annual Frequency Control Symposium, 1988..

[2]  J. Graffeuil,et al.  Microwave characterization of high Tc superconductors with a dielectric resonator , 1990 .

[3]  J. Turneaure,et al.  Microwave Surface Resistance of Superconducting Niobium , 1968 .

[4]  W. L. Holstein,et al.  Tl2Ba2CaCu2O8 films with very low microwave surface resistance up to 95 K , 1992 .

[5]  N. Klein,et al.  Survey of microwave surface impedance data of high-Tc superconductors—Evidence for nonpairing charge carriers , 1990 .

[6]  W. L. Holstein,et al.  High T/sub c/ superconductor and III-V solid state microwave hybrid circuits , 1993, IEEE Transactions on Applied Superconductivity.

[7]  R. C. Taber,et al.  A parallel plate resonator technique for microwave loss measurements on superconductors , 1990 .

[8]  D. Blair,et al.  High Q tunable sapphire loaded cavity resonator for cryogenic operation , 1989 .

[9]  J.T. Haynes,et al.  Cooled, ultra-high Q, sapphire dielectric resonators for low noise, microwave signal generation , 1991, Proceedings of the 45th Annual Symposium on Frequency Control 1991.

[10]  Y. Kobayashi,et al.  Resonant Modes of a Dielectric Rod Resonator Short-Circuited at Both Ends by Parallel Conducting Plates , 1980 .

[11]  H. Halama,et al.  Measurement of the Surface Resistance of Superconducting Lead at 2.868 GHz , 1968 .

[12]  S. J. Fiedziuszko,et al.  Dielectric resonator used as a probe for high T/sub c/ superconductor measurements , 1989, IEEE MTT-S International Microwave Symposium Digest.

[13]  P. Merchant,et al.  Processing and yield of Y/sub 1/Ba/sub 2/Cu/sub 3/O/sub 7-x/ thin films and devices produced with a BaF/sub 2/ process , 1991 .

[14]  D. Kajfex,et al.  Dielectric Resonators , 1986 .