Generation of intermodulation products by granular YBa 2 Cu 3 O 7-x thick films

Abstract

Two tone tests performed on resonators and filters fabricated from YBCO thick film coated, three dimensional resonators, indicate the importance of understanding intermodulation distortion. The films in this investigation were produced by reactive texturing and melt processing. The generation of third order intermodulation (IMD) products was observed at elevated if power levels. Correlation between IMDlevel and if field dependence of surface impedance is demonstrated. The contribution of grain boundaries to IMD is discussed in terms of the resistively shunted junction model.

Relaxation of Microwave Nonlinearity in a Cuprate Superconducting Resonator

“…The production of spurious frequencies occurs when the device is driven with a current I at high frequency and the voltage responds nonlinearly as V=I⋅Z(I), where the impedance Z of the superconducting transmission line depends on the current. Feeding current into the device at frequencies f 1 and f 2 produces harmonics, as well as mixing at sum and difference frequencies, which can be predicted by a Taylor expansion of V=I⋅Z(I) [6]. The 2nd order term of the two-frequency Taylor series expansion includes frequencies 2f 1 , 2f 2 , f 2 +f 1 , and f 2 -f 1 .…”

Microwave nonlinearity and photoresponse of superconducting resonators with columnar defect micro-channels

“…In this work, a patterned superconducting transmission line resonator implanted with a microchannel was used in order to investigate the nonlinear electrodynamics of the microchannel. Two effects of nonlinearity are (1) a microwave current dependent Q factor and resonant frequency 10 , and (2) frequency effects of the current leading to harmonic and intermodulation distortion (IMD) 11 . These nonlinear effects have informed our understanding of superconducting electrodynamics.…”

“…Sample 1 was irradiated with a fluence of 5x10 11 superconducting, completely suppressing the fundamental resonance, though not the next resonance at 2.0 GHz.…”

“…Two effects of nonlinearity are (1) a microwave current dependent Q factor and resonant frequency 10 , and (2) frequency effects of the current leading to harmonic and intermodulation distortion (IMD) 11 . These nonlinear effects have informed our understanding of superconducting electrodynamics.…”