Electromagnetic plane wave diffraction by a cylindrical arc with edges: H-polarized case

An accurate hybrid method (numerical-analytical method) for the diffraction of H-polarized electromagnetic plane wave by perfectly electric conducting cylindrical bodies containing edges and a longitudinal slit aperture is proposed. This method is the combination of the Method of Moment and semi-inversion method. The current density function is expressed as the Chebyshev polynomials forming a complete orthogonal set of basis functions. Then, the initial problem is reduced to a system of linear algebraic equations. After inversion, the unknown coefficients are obtained. Then, near and far-field distributions, radar cross-sections are obtained. The resonances are observed for different values of the aperture size, radius of the arc, and the results are compared with previous outcomes.

Degeneracy of light scattering and absorption by a single nanowire

We theoretically and numerically prove that under an electromagnetic plane wave with linear polarization incident normally to a single nanowire, there exists a power diagram that could indicate scattering properties for any system configurations, material parameters, and operating wavelength. We demonstrate the distinct power distribution boundary in absorption, scattering, and extinction for a generalized nanowire with any partial wave modes dominant. In the boundary, each dominant scattering coefficients remain constant, and its energy performance would display superabsorbers or superscatterers. Interestingly, for a system with larger partial wave modes dominant, the occupied domain in the power diagram could completely cover that with lower ones. Hence, a system with different levels of partial wave modes can display the same power results, reflecting the degeneracy. This degenerate property could release more degrees of freedom in design of energy harvesting devices and sensors. We demonstrate several systems based on realistic materials to support our findings.

A Novel Processing for CNT-Reinforced Mg-Matrix Laminated Composites to Enhance the Electromagnetic Shielding Property

The microstructure, electrical conductivity, and electromagnetic interference (EMI) shielding effectiveness (SE) of CNTs/Mg Matrix composites prepared by accumulative roll bonding (ARB) were systematically investigated to understand the effects of CNTs on the electromagnetic interference shielding effectiveness property of magnesium. A model based on the shielding of the electromagnetic plane wave was used to theoretically discuss the EMI shielding mechanisms of ARB-processed composites. The experimental results indicated that the methods were feasible to prepare laminated composites. The SE of the material increased gradually with the increase of electrophoretic deposition time. When the electrophoretic deposition time reached 8 min, the value of SE remained 87–95 dB in the frequency range of 8.2–12.4 GHz. The increase in SE was mainly attributed to the improvement in the reflection and multiple reflection losses of incident electromagnetic wave due to the increased amounts of CNTs and interfaces. The methods provided an efficient strategy to produce laminated metal matrix composites with high electromagnetic shielding properties.

Degeneracy of Light Scattering and Absorption by a Single Nanowire

We theoretically and numerically prove that under an electromagnetic plane wave with linear polarization incident normally to a single nanowire, there exists a power diagram that could indicate scattering properties for any system configurations. We demonstrate the distinct power distribution boundary in absorption, scattering, and extinction for a generalized nanowire with any partial wave modes dominant. In the boundary, each dominant scattering coefficients remain constant, and its energy performance would display superabsorbers or superscatterers. Interestingly, for a system with larger partial wave modes dominant, the occupied domain in the power diagram could completely cover that with lower ones. Hence, a system with different levels of partial wave modes can display the same power results, reflecting the degeneracy. This degenerate property could release more degrees of freedom in designs of energy harvesting devices and sensors. We demonstrate several systems based on realistic materials to support our findings.

The Diffraction by the Half-plane with the Fractional Boundary Condition

In this article, there is considered the electromagnetic plane wave diffraction by the half-plane with fractional boundary conditions. As a mathematical tool, the fractional calculus is used. The theoretical part is given based on which the near field, Poynting vector and energy density distribution are calculated. Interesting results are obtained for the fractional order between marginal values, which describes a new type of material with new properties. The results are analyzed.

Влияние пространственной дисперсии в металлах на оптические характеристики биметаллических плазмонных наночастиц

The problem of diffraction of an electromagnetic plane wave field on a core-shell nanoparticle composed of two plasmon metals is considered. The effect of spatial dispersion in metals on the absorption cross section is investigated on the basis of the Discrete Sources method. Various combinations of core and shell metals: Au@Ag and Ag@Au of spheroidal particles, as well as the effect of elongation and asymmetry of particle geometry on energy absorption are being studied. It was found that taking into account the spatial dispersion, both in the core and in the shell, leads to a significant decrease in the absorption cross section and a shift of the plasmon resonance to the shorter wavelength region.

Анализ поглощающих периодических структур, образованных цилиндрическими электромагнитными черными дырами

A 2D problem of electromagnetic plane wave scattering by 1D-periodic structures composed of cylindrical black holes arranged on a semi-infinite substrate is considered. Two algorithms corresponding to the cases of E- and H-polarization and based on the hybrid projection method accounting for the refractive index profiles in the black holes of a few types are developed. The algorithms are generalized also on the case of arrangement of the black holes on a PEC screen. A number of numerical results characterizing both the effectiveness of the algorithms themselves and performance of the absorbing structures with black holes are presented. Absorbing characteristics of the indicated structures are compared to the similar characteristic obtained for the structures of wedge elements.