I. P. Korshunov

Plasmon resonances in a quartz nanofiber coated with a silver layer

A 2D problem of diffraction of the TM-polarized plane wave by a quartz nanofiber coated with a silver layer is investigated. The total scattering cross-section is numerically calculated in the range of visible light waves (400–700 nm). It is found that, at certain geometric parameters of the structure, not only dipole but also multipole plasmon resonances arise in the investigated range of wavelengths. Scattering patterns at resonance frequencies are calculated. It is demonstrated that deposition of the silver layer onto a quartz nanofiber can decrease the scattering cross section several times.

The field of a point source near planar and cylindrical boundaries of a metamaterial

The properties of the two-dimensional electromagnetic fields excited by a filamentary source located near planar and cylindrical boundaries of bodies made of metamaterials with their permittivity and permeability close to minus one are considered. The subwavelength field localization effects, the phenomena associated with the resonances of surface waves, and the nonresonant field enhancement effects are investigated.

Frequency-selective screens and radiating and guiding structures based on anisotropically conducting surfaces

Three types of elements with an anisotropically conducting surface—a strip, a cylinder, and a sphere—that are of interest for certain applications are considered. It is shown that these electrodynamic objects exhibit resonance properties even when their dimensions are small compared to the wavelength and that resonances occur in both 2D and 3D diffraction problems. It is found that the presence of low-frequency resonances provides for a wide variety of electrodynamic properties of the objects under study and of gratings formed from such elements. Examples of implemented waveguides, waveguide mode converters, frequency-selective circular-polarization antennas, and polarization transducers are presented.

High-Q resonanaces of surface waves in thin metamaterial cylinders

The 2D problem of excitation of a circular metamaterial cylinder by a filament source is numerically investigated. It is found that, when the relative permittivity and permeability are close to minus unity, high-Q resonances occur in cylinders of an electrically small diameter. Near- and far-field patterns are calculated. It is discovered that, under resonance conditions, a multilobe scattering pattern typical of superdirective antennas is formed. The influence of loss on the resonance characteristics is investigated.

Quasi-static plasmon resonances in a graphene ribbon in the infrared range

The 2D problem of diffraction of a plane electromagnetic wave diffraction by a graphene ribbon is considered for the case of the TM polarization. Quasi-static plasmon resonanses are investigated with the use of rigorous numerical methods. The surface currents and scattering and absorption cross-sections are calculated. It is shown that, owing to the high Q-factor, multipole plasmon resonances appear not only in the near field but also in the far field.

Degeneracy of low-frequency resonances in a chiral anisotropically conducting cylinder filled with a metamaterial

The paper considers the 2D problem of a cylinder, filled with a metamaterial with anisotropic surface conductivity along helical lines, excited by electric and magnetic field filaments. High-Q resonances occurring in small (as compared to the wavelength) cylinders with a permeability close to −1 are investigated. The effect of degeneracy of oscillations with various values of index m in the cos(mφ) law describing the azimuthal dependence of resonant fields is discovered. The range of parameters in which degenerate oscillations exist is determined. The spatial and polarization structures of magnetic fields are analyzed. An analytic description is proposed for resonant fields in the quasi-static approximation.

Selection of the microwave-beam parameters in a wireless system for energy transportation from a space electric power station to the Earth

An algorithm for finding the parameters of the microwave beam used for power transportation from a space electric power station to the Earth is considered. It is shown that, for specified geometries of antenna and rectenna systems, it is possible to increase the received power if the density of the radiated power at the antenna center and the truncation parameter of the Gaussian field distribution are simultaneously increased. It is found that, in this case, the transmission efficiency decreases only slightly as compared to the case of optimum transmission.

Plasmon resonances in a silver elliptical cylinder surrounded by a confocal elliptical glass shell

Plasmon resonances occurring in a 2D problem of diffraction of a plane wave by a silver cylinder enclosed in a glass shell are studied under the assumption that the media interfaces are shaped as confocal ellipses. Scattering and absorption spectra in the optical range are calculated using strict numerical techniques. The obtained analytical expressions allow resonance parameters of the structure to be obtained in the quasi-static approximation.

On the influence of the medium loss on resonances of surface plasmons in a cylinder

Two-dimensional problem of excitation of a circular cylinder made of a material with negative permittivity by a plane or a cylindrical wave is considered for the case of TM polarization. Conditions under which resonances of surface plasmons arise in cylinders thin compared to the wavelength are found with the use of strict numerical calculations.

The resonance properties of multiturn wire helices filled with a metamaterial

The 2D problem of the excitation of a multiturn cylindrical wire helix filled with a metamaterial by electric- and magnetic-current filaments is considered. High-Q resonances in the low-frequency region are found and investigated. It is shown that, depending on the values of the constitutive and geometric parameters of the anisotropically conducting cylinder, the resonance fields can have both linear and circular polarizations. On the basis of a rigorous calculation, the amplitude-frequency characteristic of this structure and near- and far-field patterns are considered. Approximate analytic expressions are obtained for the resonance frequencies.