Correction to "Nonlinear Analysis of Disk Resonators: Application to Material Characterization and Filter Design

A procedure for the numerical prediction of the microwave nonlinear behavior (intermodulation products, degradation of quality factors, etc.) of TM010 disk resonators has been developed. The procedure is based on relating a very general description of HTS nonlinearities with the circuit elements of a nonlinear radial transmission line. This radial transmission line is then analyzed using the harmonic balance algorithm. Successful cross-checks are performed by comparing simulations with theoretical results obtained for a specific model of HTS nonlinearity. The application of this procedure to the determination of nonlinear material parameters from disk resonator measurements is illustrated as well as its use for simulating filters with several inter-coupled disks. Correction: J. Mateu, IEEE Trans. Appl. Superconduct., vol. 11, pp. 135–138, Mar. 2001. On p. 137 of the above paper, the first sentence of the paragraph immediately following equation (14) should read as follows.Peer Reviewe

Nonlinear Analysis of Disk Resonators. Application to Material Characteritzation and Filter Design.

A procedure for the numerical prediction of the microwave nonlinear behavior (intermodulation products, degradation of quality factors, etc.) of TM010 disk resonators has been developed. The procedure is based on relating a very general description of HTS nonlinearities with the circuit elements of a nonlinear radial transmission line. This radial transmission line is then analyzed using the harmonic balance algorithm. Successful cross-checks are performed by comparing simulations with theoretical results obtained for a specific model of HTS nonlinearity. The application of this procedure to the determination of nonlinear material parameters from disk resonator measurements is illustrated as well as its use for simulating filters with several inter-coupled disks.Peer Reviewe

Analysis and Simulation of Distributed Nonlinearities in Ferroelectrics and superconductors for Microwave Applications

This paper gives closed-form equations for the intermodulation and third harmonic signals generated in a nonlinear transmission line with distributed quadratic nonlinearities in the conductor and dielectric. Although the formulation developed is general, it is intended to be used in planar devices combining high-temperature superconductor (HTS) and oxide ferroelectrics. The analysis in this paper shows that the intermodulation and third harmonic signals produced by an HTS tend to cancel those of a ferroelectric, and that full cancellation is theoretically possible. This opens the way for using HTS/ferroelectric multilayers, not (only) for their tunable or phase-shifting properties, but for highly linear spurious-free planar HTS devices.Peer Reviewe

La visualització dels col·lectius estrangers a la ràdio i a la televisió de proximitat

L'objectiu de l'article és analitzar la representació de la població estrangera als mitjans de comunicació audiovisual d'àmbit local, partint de la hipòtesi que la proximitat a l'entorn social contribueix a abordar el fet migratori i la diversitat cultural en clau de cohesió social i de convivència. L'anàlisi de l'oferta dels diferents mitjans, però, evidencia el baix índex de propostes programàtiques i revela l'absència de referents mediàtics que estimulin la creació de vincles emocionals entre els ciutadans nouvinguts i la societat d'acollida. Des de la perspectiva de les associacions d'immigrants, es posa de manifest que la tensió i el conflicte social són els factors que en determinen, en bona part, la presència als mitjans.The aim of this paper is to analyze the representation of foreign people in local media. It is based on the hypothesis that proximity to social environment contributes to properly explain immigration and cultural diversity. The analysis of the TV and radio chart demonstrates the existence of few TV and radio programs that enhance emotional links between immigrants and local population. From immigrant associations perspectives, is made manifest that tension and social conflict continue to be the main factors determining their presence in mass media

Hilbert fractal curves for HTS miniaturized filters

This work presents novel compact High Temperature Superconductor (HTS) microstrip resonators based on Hilbert fractal curves. Their miniaturization performance has been investigated, emphasizing the parameters which allow to obtain a good trade off between compact size and quality factor. Hilbert resonators with different arrangements have been designed and assessed by using full wave simulators. In order to experimentally verify our analysis, a four pole quasi elliptic filter, in the cascade quadruplet configuration, with f0 close to 2.45GHz, have been fabricated by patterning a 10x10mm2 YBCO film on MgO substrates. Minimum insertion losses of the order of (0.1-0.2) dB have been measured.Peer Reviewe

Nonlinear performance characterization in an eight-pole quasi-elliptic bandpass filter

In this work we predict the nonlinear behaviour of an eight-pole quasi-elliptic bandpass high temperature superconducting (HTS) filter with an equivalent circuit extracted from intermodulation measurements performed at the centre of the filter passband. We present measurements that show that the equivalent circuit is able to predict the intermodulation products produced by the filter when driven by two in-band or out-of-band sinusoidal signals. Numerical techniques based on harmonic balance are used to extract the elements of the equivalent circuit and to simulate its nonlinear performance.Peer Reviewe

Miniaturization of superconducting filters using Hilbert fractal curves

This work presents novel compact high-temperature superconductor microstrip resonators and filters based on the Hilbert space-filling fractal curve. Several Hilbert resonator configurations have been assessed by using a full-wave electromagnetic simulator and their miniaturization performance has been investigated, emphasizing the parameters which allow obtaining good tradeoff between compact size and losses. These resonators have proved to be useful for filter design. A four-pole 2.45-GHz quasi-elliptic filter and a four-pole 1.9-GHz Chebyshev filter have been realized by patterning 10 mm/spl times/10 mm Y/sub 2/Ba/sub 3/Cu/sub 7-/spl delta//O thin films on MgO substrates. Insertion losses of the order of 0.2 dB have been measured, showing good agreement with the simulations.Peer Reviewe

Nonlinear Distortion in a 8-Pole Quasi-Elliptic Bandpass HTS Filter for CDMA System

High Temperature Superconductor materials are known to produce intermodulation and other nonlinear effects which may restrict their use in wireless communication systems. Quantifying this degradation is crucial in determining if the use of HTS filters in the receiver is beneficial. In this work we use an approach for representing the HTS filter nonlinear equivalent circuit and simulating its performance. We have tested the approach on a planar, 8-pole quasielliptic (QE) filter, showing agreement between simulations and measurements of intermodulation products (IMD). The nonlinear equivalent circuit is then used to predict the nonlinear behavior of the filter and its effects on system parameters when it is subject to broadband signals like those used in wireless communication systems.Peer Reviewe