YBCO X-BAND MICROSTRIP LINEAR RESONATORS ON (1(1)OVER-BAR-02)-ORIENTED AND (1(1)OVER-BAR-00)-ORIENTED SAPPHIRE SUBSTRATES

YBa2Cu3O7-delta (YBCO) films on sapphire substrates have been tested f or planar microwave applications such as filters and resonators, We ha ve measured the unloaded quality factors (Q(o)) of X-band microstrip l inear resonators patterned into YBCO films on R-plane (1 (1) over bar 02-oriented) and M-plane (1 (1) over bar 00-oriented) sapphire substra tes with CeO2, and MgO buffer layers, respectively. For the films on M -plane sapphire, the T-c and x-ray FWHM values were 87-88 K and 1.2 de grees, respectively, while for those on R-plane sapphire the values we re 88-89 K and 0.4 degrees. Despite the superior properties of the fil ms on R-plane, the YBCO on M-plane sapphire resonators had Q(o) values over 2000 at 77 K while those on R-plane sapphire had Q(o) values of less than 600. This could be correlated with the anisotropy of the R-p lane sapphire as evidenced by the observed dependence of the shape of the resonance on the orientation of the resonator relative to the in-p lane direction of the substrates. Possible causes for this behavior wi ll be discussed.