Papers by Keyword: Left-Handed Material (LHM)

Abstract: Left-handed Materials (LHM) is a kind of structural materials of artificial cycle which permittivity ε and permeability μ are both negative. This article mainly studied the electromagnetic scattering characteristics of LHM by using the method of rigorous modal matching, and discussed the variation of corresponding elliptical eccentricity, its loss and negatively permittivity on the effect of radar cross section by numerical calculation .

Abstract: Left-handed material (LHM), whose permittivity and permeability are both negative, has attracted much attention due to its exotic electromagnetic properties, such as negative refraction, backward wave propagation and evanescent wave amplification. The microwave left-handed property of a composite medium composed of ferrite cubes’ array and copper net was studied using the method of finite difference time domain in this paper. An obvious left-handed pass band emerged when ferrite cubes were combined with longitudinal copper wires, because the ferrite produced negative permeability by the ferromagnetic resonance and the copper wires produced negative permittivity by the plasma. With the addition of horizontal copper wires, the transmission intensity of the pass band was gradually weakened. It can be concluded that the horizontal wires played a negative role in realizing the composite LHM with ferrite cubes and copper net. This work gives an instructive direction to the fabrication of 3D LHMs.

Abstract: Based on the back propagation multi-layer forward feed neural network, the neural network model is built for the dielectric sensitive structural parameters between the equivalent permittivity and the equivalent permeability, which is used to analyze the basic left-hand materials(LHMS) structural. The experimental results show that the analysis time is 145.535648 seconds and the training mean error is 0.000113426 while adopting the scaled conjugate gradient method. The results are coincident with these ones by the full wave method, satisfying the engineering demand, reducing the faults caused by thickness resonance in the traditional numerical analysis method, realizing the coexistence between the high analysis precision and the high efficiency of the left-hand materials.

Abstract: An analytical direct matching procedure within the Kronig-Penney model applied to analyze the dispersion behavior of the localized surface states supported in the surface of a semiinfinite one-dimensional photonic crystals truncated with air. The photonic crystal containing alternating layers of positive and negative media. In the case of the conventional indices, as the incident light changes from normal to oblique incidence, the surface modes shifts into higher frequencies. For this reason, the phenomenon of photonic band gap has been used only under a narrow range of frequencies of light incident at a particular angle or in a particular angular range. We have showed that by choosing some proper value for the PC parameters, zero and negative dispersion of surface modes emerge in a large range of k|| , and, due to the different nature of the band structure the surface modes are more localized compared to those appeared in the conventional PC.