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HF power-induced nonlinear effects, including the two-tone intermodulation distortion (IMD), were examined by using 2.3 GHz microstrip resonators prepared from double-sided YBa[sub 2]Cu[sub 3]O[sub 7-ℵ] (YBCO) and GdBa[sub 2]Cu[sub 3]O[sub 7-ℵ] (GBCO) films on CeO[sub 2] buffered sapphire. Both, the YBCO and the GBCO resonators exhibited similarly high performance with low IMD level. The third-order interception points varied linearly with temperature from P[sub TOI] ≈ 1500 W of the circulating power, P[sub circ], at 4.2 K to P[sub TOI] ≈ 90 W at 77.4 K. The dependence of the IMD products on the P[sub circ]/P[sub TOI] ratio was found to be the same at all measurement temperatures. Similarly, the variation of the microwave surface resistance ΔR[sub s] versus P[sub circ]/P[sub TOI] was found to be temperature-independent. The combination of these dependences provided an universal relation between the power of the IMD signals and &ΔRs, which was exhibited by both YBCO and GBCO resonators in the entire examined temperature range. [ABSTRACT FROM AUTHOR]

Studies the effect of an Au contact layer on the microwave performance of YBa[sub 2]Cu[sub 3]O[sub 7-gamma] superconductor thick films. Microwave measurements; Power handling capability of a disk resonator made from thick YBCO superconducting film; Variation in the effective London penetration depth with temperature.

Studies YBCO thin films deposited by sputtering on buffered sapphire wafers. Lateral homogeneity; Surface resistance; Quality of the sputtered films; Applications in superconducting high frequency devices.

We prepared and tested dielectric resonators designed for a two pole filter. These resonators were LaAlO/sub 3/ single crystalline cylinders which were covered on the end faces by about 350 nm YBa/sub 2/Cu/sub 3/O/sub 7-/spl delta// thin films and on the cylindrical surface by 4 /spl mu/m gold films. The YBa/sub 2/Cu/sub 3/O/sub 7-/spl delta// films were c-axis oriented with mosaic spreads of about 0.3/spl deg/. The inductive transition temperatures were above 90 K. The HF properties were characterized by evaluation of the H/sub 011/ mode at 8.05 GHz, and by measuring the surface resistance at 18.9 GHz. At 77 K the Q-value of this resonance was typically 12000, which is about a factor of 2 higher than the Q-value of 6560 found for end faces covered with pure copper. From these resonators two-pole bandpass filters were constructed that at 77 K showed an insertion loss of -0.26 dB at their center frequency of 6.3 GHz. [ABSTRACT FROM PUBLISHER]