Co-doped Zn1−xCoxAl0.01O (x=0.15,0.3) and (Mn, Co) codoped Zn0.7(Mn0.15Co0.15)O thin films were fabricated on Al2O3 (0001) by pulsed laser deposition. The doped ZnO with well wurtzite structures could be deposited at a low temperature of 400 °C oxygen pressure 5×10−5 Pa. showed metallic conductivity resistance, while the was semiconductor high which confirmed resistance vs measurements. All three room (290 K) ferromagnetism, saturated magnetic moments 0.08μB/Co, 0.17μB/Co,...

In this work, a finite-difference time-domain (FDTD) method is employed to justify the superlensing effect of left-handed material (LHM) slabs. Our results demonstrate that subwavelength resolution can be achieved by LHM slabs with certain parameters. We present dynamic feature imaging process and dependence physical parameters on performance superlens. These help clarify diverse FDTD reported previously. also show achievable limited absorption thickness slabs, which introduces difficulties...

We carry out finite-difference time-domain simulations, with a specially designed boundary condition, on pure evanescent waves interacting lossy left-handed material (LHM) slab. Our results provide the full-wave numerical evidence for amplification of inside LHM slab finite absorption. The is due to interactions between and coupled surface polaritons at two surfaces physical process can be described by simple model.

The perfectly matched layer (PML) absorbing boundary condition (ABC) is extended to truncate the of left-handed materials in Finite-Difference Time-Domain (FDTD) simulation. uniaxial material parameters are given frequency domain, and discretized FDTD update procedure by means Z-Transform technique. effectiveness PML demonstrated numerical results.

Microwave transmission through one-dimensional metallic compound grating is studied up to $18\phantom{\rule{0.3em}{0ex}}\mathrm{GHz}$. The consists of a basic unit one slit ($a$ type), two slits ($ab$ and three ($abc$ type) different widths. Greatly enhanced observed at the frequencies near first second order waveguide harmonics. splitting peak found for $ab$- $abc$-type grating. This effect explained by multiphase patterns $E$-field distributions inside slits, predicted numerical...

Three modified proportional topology optimization (MPTO) algorithms are presented in this paper, which named MPTOc, MPTOs and MPTOm, respectively. MPTOc aims to address the minimum compliance problem with volume constraint, solve fraction under stress MPTOm tackle constraints. In order get rid of shortcomings original (PTO) algorithm improve comprehensive performance PTO algorithm, proposed modify material interpolation scheme introduce Heaviside threshold function based on algorithm. To...

An improved proportional topology optimization (IPTO) method is proposed in this work. The main improvement of that the conventional solid isotropic material with penalization (SIMP)-based interpolation scheme replaced by a polarized scheme, and Heaviside threshold function adopted based on original (PTO) method. By using approach, minimum compliance problem can be solved without requiring numerical derivation sensitivity function. To verify feasibility effectiveness method, two-dimensional...

A microstrip bandpass filter implemented with dual-spiral resonators is described in this letter. The make the compact and allow implementation of positive negative inter-resonator couplings. Implementation couplings used to introduce a pair finite frequency transmission-zeros response. two zeros are designed be close passband, thus improving selectivity filter. As an example, four-stage cross-coupled fabricated using superconducting YBa/sub 2/Cu/sub 3/O/sub 7-/spl delta// thin films...

By incorporating an anomalous weak link (AWL), the coupled-grain model is modified to describe decrease of microwave surface impedance (Zs) YBa2Cu3O7-δ thin films in a dc magnetic field (Bdc). The critical current density AWL has minimum at zero Bdc, linear dependence on Bdc for low and saturation high unlike conventional link. Using this model, dependences resistance are calculated different rf input powers resonant modes. dimensionless parameters rH, defined as ratio change reactance, also...

A novel type of one-dimensional microstrip bandstop filters with continuous patterns is proposed based on Fourier transform. These are capable realising single or multiple stopbands at desired frequencies. This design method simple but powerful, and confirmed by both simulation experimental results.

Abstract A broadband left‐handed parallel‐line microstrip coupler is implemented by both electromagnetic simulation and actual fabrication. The circuit dimensions are smaller more compact than those in previous studies a thinner Duroid substrate of thickness h = 0.635 mm used. Parametric were performed using IE3D, fabrication was done via Quick Circuit 7000 prototyping machine. network‐analyser measurements indicate broad bandwidth coupling the 6.5–7.7‐Ghz region. © 2005 Wiley Periodicals,...

An epitaxial La0.67Sr0.33MnO3 thin film covered with a monolayer of colloidal spheres was ion-milled so that structural discontinuities were involved. Nonlinear V-I characteristics have been observed, revealing the zero-field resistance sample decreases increasing measuring current I. In magnetic field, however, varies non-monotonically inflexion appears around I = 50 nA. Accordingly, magnetoresistance also correlates A maximum value as high − 700% (ΔR/RH) is recorded at liquid nitrogen in...

In this work the electromagnetic interactions in metallic reflection gratings of subwavelength periods were investigated. The modified by inner air gaps introduced between metal slats and conducting ground plane. Fabry–Pérot-like modes excited within grating slits (the cavities adjacent slats), depending on gap width, frequency locations as well mode orders changed. Additional resonance both evanescent propagating types would be inside gap. They interact with fields to form hybrid...

The magnetic-field-induced decrease of microwave surface impedance, Zs=Rs+jXs, superconducting YBa2Cu3O7−δ thin films is investigated using a microstrip resonator technique. Through measuring Zs as the direct current (dc) magnetic field increased from zero to certain value Hmax and subsequently decreased back zero, it found that Zs(Hdc) totally reversible if does not exceed threshold H*, at which Rs shows minimum, while irreversible larger than H*. It confirmed anomalous effect happens in...

A novel method, in which a multi-bandwidth measurement technique and an extrapolation procedure are combined, is proposed for extracting the loaded Q-factor (QL) with improved accuracy from non-Lorentzian resonances of nonlinear superconducting resonators.

An unusual microwave response of the surface impedance Zs high-Tc thin films at an applied small dc magnetic field (Bdc) 77 K, namely a decrease Zs, is observed with microstrip resonator technique. The resonant frequency 1.107 GHz. direction Bdc parallel or perpendicular to a-b plane. ranges from 0 200 G. It found that resistance (Rs) plane first decreases and then increases above crossover field. Rs behaviour for same but different two behaviours can be collapsed one curve by scaling...