Surface resistance and nonlinear dynamic microwave losses of epitaxial HTS films

Analysis and Simulation of distributed nonlinearities in ferroelectrics and superconductors for microwave applications

“…While this intrinsic contribution sets the minimum level of nonlinearities [13], other extrinsic nonlinearities due to material defects may further enhance nonlinear distortions [14]- [16].…”

Application of a one-port dielectric resonator for measurement of the intermodulation in high temperature superconducting films

“…The effect of frequency transformation may appear at much lower field values than the change of R s . 1 In microwave devices in the presence of two fundamental signals, f 1 and f 2 , the nonlinearity of film leads to the appearance of spurious output at mixed frequencies f comb1 ϭ2 f 1 Ϫ f 2 and f comb2 ϭ2 f 2 Ϫ f 1 . Therefore measurement of the output power at mixed frequency P comb as a function of input power P in allows us to determine the important parameter of HTS film directly influencing the device characteristics.…”

“…[1][2][3][4][5] A low value of the surface resistance R s of such films opens the opportunity for development of high quality resonators, filters, and other microwave devices. At the same time for several applications such as filters, the nonlinear effects cause the degradation of their performance at high power densities.…”

“…At the same time for several applications such as filters, the nonlinear effects cause the degradation of their performance at high power densities. [1][2][3][4][5] The microwave nonlinear performance of the films is governed by the physical properties of the material itself ͑in-trinsic͒ and the defects attributed to fabrication technology features ͑extrinsic͒. 6 It is important to note that high values of critical temperature and critical current and low R s measured at low power do not guarantee weak nonlinearity of the film, 1 therefore, optimization of the nonlinearity diagnostics must be performed by the deposition procedure.…”

“…Currently, various types of resonators with two coupling probes are employed to evaluate the nonlinearity in HTS films. [1][2][3] Essentially, one coupling element serves as an input for high-power pumping signals at frequencies f 1 and f 2 , while the second one outputs both the fundamental ͑pump-ing͒ and IM signals. The main disadvantage of such systems is the appearance of high-level pumping signals in the output line at frequencies close to the low-level IM signals.…”