Plane Electromagnetic Wave Research Articles

Transverse Kerker Effect for Dipole Sources.

Transverse Kerker effect is known by the directional scattering of an electromagnetic plane wave perpendicular to the propagation direction with nearly suppression of both forward and backward scattering. Compared with plane waves, localized electromagnetic emitters are more general sources in modern nanophotonics. As a typical example, manipulating the emission direction of a quantum dot is of vital importance for the investigation of on-chip quantum optics and quantum information processing. Herein, we introduce the concept of transverse Kerker effect for dipole sources utilizing a subwavelength dielectric antenna, where the radiative power of magnetic, electric, and more general chiral dipole emitters can be dominantly redirected along their dipole moments with nearly suppression of radiation perpendicular to the dipole moments. This type of transverse Kerker effect is also associated with Purcell enhancement mediated by electromagnetic multipolar resonances induced in the dielectric antenna. Analytical conditions of transverse Kerker effect are derived for the magnetic, electric, and chiral dipole emitters. We further provide microwave experiment validation for the magnetic dipole emitter. Our results provide new physical mechanisms to manipulate the emission properties of localized electromagnetic source which might facilitate the on-chip quantum optics and beyond.

Scattering of a plane wave by an inhomogeneous 1D dielectric layer with gradient refractive index

We propose a new method for calculating reflection and transmission coefficients for an arbitrarily polarized electromagnetic plane wave incident on a one-dimensional dielectric medium of finite thickness and with dielectric permittivity being an arbitrary continuous function of the coordinate. We have shown that the problem of plane wave scattering by an inhomogeneous layer is reduced to a system of first order differential equations that contain the derivative of the refractive index or dielectric permittivity of the layer, which can be used, for example, when searching for an analytical solution. This method also makes it easy to obtain the distribution of the field strength within the layer. The reflection spectra and field distribution obtained using this method were compared with the analytical solution based on Mathieu functions.

Resonant absorption of electromagnetic waves by an induced inhomogeneity in a liquid metamaterial

In this study, we consider the scattering of a plane electromagnetic wave on a cylindrically inhomogeneous distribution of meta-atoms in a liquid metamaterial. The distribution inhomogeneity appears naturally as a result of the application of an electric potential to an electrode immersed in the liquid metamaterial, which leads to the appearance of inhomogeneity in the effective permittivity of such a medium. Consequently, in the considered type of metamaterial, the concentration-dependent effective permittivity can become negative in some region of space. In the vicinity of the interface between positive and negative permittivity, the behavior of the electromagnetic wave becomes singular, giving rise to effects such as resonant absorption, resonant scattering, and shielding of the central region. These effects can be controlled in real time by changing the applied electric potential and thus rearranging the liquid metamaterial.

Optical response of dielectric&metal-core/metal-shell nanoparticles: Near electromagnetic field and resonance frequencies

We study the diffraction of a monochromatic electromagnetic plane wave by a dielectric&metal-core/metal-shell nanoparticle surrounded by a dielectric medium. This problem was solved by using generalized Mie’s theory and both the scattering cross section and the square module of the electric field were calculated as a function of shell thickness. Numerically, the first particles studied were gold-core/silver-shell nanoparticles and their inverse configuration. The gold-core/silver-shell particle presented more variation of their optical properties. The second particles were vacuum-core/metal-shell surrounded by vacuum, symmetric configurations. In this case, the dispersive Drude dielectric function for the metal was used, and a comparative study between the positions of the resonance frequencies obtained from quasi-static limit and electrodynamic theory was performed. Thus, consequently the formula obtained from the quasi-static limit can be used to calculate the positions of the resonance frequencies instead of the electrodynamic theory, when the external radius is smaller than 20 nm.

On the Far Field Patterns for Electromagnetic Scattering in Two Dimensions

We consider the problem of scattering time-harmonic electromagnetic plane waves by a dielectric infinitely long cylinder with core which may be a perfect or an imperfect conductor. The corresponding scattering problems are reduced to mixed boundary value problems for the two-dimensional Helmholtz equation . For the far field patterns of these problems, we prove a reciprocity principle and a general scattering theorem. The combination of these theorems with Herglotz wave functions leads to the proof of some properties of the far field operator, which are used in the study of inverse scattering problems. Finally, an optical theorem for the above scattering problems is proved.

Diffraction by a Perfect Electromagnetic Conductor Half-Plane in an Anisotropic Plasma: An Integral Theory Approach

The diffraction of plane electromagnetic waves by a perfect electromagnetic conductor (PEMC) semi-infinite sheet which is embedded in an anisotropic medium is examined. The anisotropic region is modeled by a dielectric matrix. The external uniform magnetic field is taken as parallel to the edge of the semi-infinite sheet. Upon considering the H-polarized incident wave, the total scattered fields are obtained with the diffracted waves by using an integral theory which is associated with the scattered fields. The results are expressed in terms of the Fresnel functions. Thus, the wave behaviors at the transition boundaries are uniform. The solutions are compared numerically with the literature including limit values.

Three cases of discontinuous refractive index in metamaterial study

We investigate three cases of metamaterials presented in the literature displaying refractive index with one or more discontinuities along the frequency spectrum. We reproduce the numerical simulations of these metamaterials and compare our simulations to each reported case. For each case, we perform a geometrical investigation of each metamaterial’s refractive index by mean of a numerical simulation of a prism made of the reported metamaterials upon which is incident a plane electromagnetic wave. Such investigation allows us to infirm or confirm negative refraction at resonance frequency. Finally, we carry a numerical and theoretical investigation of this discontinuity and show that, as the refractive index crosses a discontinuity, while the topology of the effective wave has changed within the metamaterial, the dynamics of the phases remain unchanged at any time at the metamaterial's boundaries.

Resonant reflection of plane microwave electromagnetic waves by the linear dielectric-ring structures

Artificial materials with negative magnetic and dielectric permittivity have unique electrodynamic properties that are not present in natural materials. We present the results of studying of the main magnetic LC resonance induced by a plane electromagnetic wave of GHz range in the linear structures of subwavelength dielectric ring elements with a high relative permittivity. The dielectric constant of the ring material (capacitor ceramics) is 160. Resonant scattering on the main magnetic mode and wave properties of linear structures consisting of subwavelength dielectric elements in the form of flat thin rings were studied. A single ring or ring structures were arranged in such a way that the vectors of the electric and magnetic fields of a plane incident electromagnetic wave were parallel to the plane of the ring, whereas the wave vector was perpendicular to the plane of the ring. Linear structures consisting of two or three rings were oriented along the magnetic vector of the incident wave. The magnetic field probe was placed on the line of the axis of symmetry of the ring and structures relative to the wave vector at the side of the structures most distant from the antenna. The spectra of transmitted radiation were measured during resonant excitation of magnetic fields in a system of dielectric rings in the near (distance — 2 mm) and remote (distance — 30 mm) zones from the ring. It is shown that in the near wave zone, splitting of the resonant frequency occurs due to mutual inductance and interaction of the rings. As the number of rings increases, the number of additional peaks also increases. A bandwidth of ~200 MHz with an amplitude 25 dB greater than the amplitude of the incident electromagnetic wave in the specified spectrum appears between the split levels. In the far zone, the transmitted radiation at the resonance frequency for a single ring practically does not change due to the splitting of this resonance frequency due to the interaction of the rings in the structure. The results obtained can be used in the development of new materials.

Dynamics of a fermion with dipole moments in external wave fields

We discuss the motion of a massive fermion spin 1/2 particle in external wave field configurations when the Pauli type non-minimal interaction of the gauge field strengths with particle’s dipole moments is taken into account. The exact solution of the relativistic Dirac-Pauli equation is presented for the case of the plane electromagnetic wave.

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.

Fast and numerically stable Mie solution of EM near field and absorption for stratified spheres

PurposeThe purpose of this paper is the development of an analytic computational model for electromagnetic (EM) wave scattering from spherical objects. The main application field is the modeling of electrically large objects, where the standard numerical techniques require huge computational resources. An example is full-wave modeling of the human head in the millimeter-wave regime. Hence, an approximate model or analytical approach is used.Design/methodology/approachThe Mie–Debye theorem is used for calculating the EM scattering from a layered dielectric sphere. The evaluation of the analytical expressions involved in the infinite sum has several numerical instabilities, which makes the precise calculation a challenge. The model is validated through an application example with comparing results to numerical calculations (finite element method). The human head model is used with the approximation of a two-layer sphere, where the brain tissues and the cranial bones are represented by homogeneous materials.FindingsA significant improvement is introduced for the stable calculation of the Mie coefficients of a core–shell stratified sphere illuminated by a linearly polarized EM plane wave. Using this technique, a semi-analytical expression is derived for the power loss in the sphere resulting in quick and accurate calculations.Originality/valueTwo methods are introduced in this work with the main objective of estimating the final precision of the results. This is an important aspect for potentially unstable calculations, and the existing implementations have not included this feature so far.

Analysis, Sources and Study of the Biological Consequences of Electromagnetic Pollution

The actions and health effects of electromagnetic fields in the radio frequency (RF) domains, referred to as radio frequencies and HV transmission networks have been studied for several decades. Following the appearance of questions and debates within the population, the actions and potential effects of radiofrequency and HV transport networks on health, in connection with the development of new wireless technologies, are generating a certain revival of interest. Thus, the increasing exposure to electromagnetic fields and the concerns of the public have led health organizations to undertake large-scale research programs to respond to the concerns expressed. These research programs have contributed to significantly increasing the number of studies on the actions and effects of electromagnetic pollution as well as their consequences on living beings. The objective of our research is focused on the analysis, sources, and study of the biological consequences of electromagnetic pollution. To do this, we have used physical laws and theorems, in particular Maxwell-Ampère, Maxwell-Gauss, Maxwell-Faraday, and Ohm’s law, to model the interactions between electromagnetic fields and living matter. In this article we have chosen the approach based on the electrical model of human biological tissue, taking into account on the one hand the physical phenomena of the propagation of an electromagnetic microwave plane wave in the range from 0 to 300GHz and on the other hand, the experimental values to simulate the relaxations α, β and γ and the impedance of the biological tissue faced with the variation of the frequency of propagation of the electromagnetic waves to identify the biological consequences relating thereto. The results obtained in the literature show the linear dependence of bio-impedance on frequency, these observations suggest that the tissue can be physiologically stressed at high frequencies. This can cause biological consequences for humans. The 2D simulation based on the proposed model has been developed as well as the verification of the consistency of the different mathematical models, by comparing the fractal dimensions of the results of the program with those of the figures obtained experimentally.

Silicon cuboid nanoantenna with simultaneous large Purcell factor for electric dipole, magnetic dipole and electric quadrupole emission

The Purcell effect is commonly used to increase the spontaneous emission rate by modifying the local environment of a light emitter. Here, we propose a silicon dielectric cuboid nanoantenna for simultaneously enhancing electric dipole (ED), magnetic dipole (MD) and electric quadrupole (EQ) emission. We study the scattering cross section, polarization charge distribution, and electromagnetic field distribution for electromagnetic plane wave illuminating the silicon dielectric cuboid nanoantenna, from which we have identified simultaneous existence of ED, MD and EQ resonance modes in this nanoantenna. We have calculated the Purcell factor of ED, MD and EQ emitters with different moment orientations as a function of radiation wavelength by placing these point radiation source within the nanoantenna, respectively. We find that the resonances wavelengths of the Purcell factor spectrum are matching with the resonance modes in the nanoantenna. Moreover, the maximum Purcell factor of these ED, MD and EQ emitters is 18, 150 and 118 respectively, occurring at the resonance wavelength of 475, 750, and 562 nm, respectively, all within the visible range. The polarization charge distribution features allow us to clarify the excitation and radiation of these resonance modes as the physical origin of large Purcell factor simultaneously occurring in this silicon cuboid nanoantenna. Our theoretical results might help to deeply explore and design the dielectric nanoantenna as an ideal candidate to enhance ED, MD and EQ emission simultaneously with very small loss in the visible range, which is superior than the more popular scheme of plasmonic nanoantenna.

Calculation of reflections of a plane electromagnetic wave of linear polarization from a layer of a chiral metamaterial located on an ideally conducting plane according to the Maxwell Garnett model

Calculation of reflections of a plane electromagnetic wave of linear polarization from a layer of a chiral metamaterial located on an ideally conducting plane according to the Maxwell Garnett model

Wideband Gain Enhancement of High-Isolation and Quasi-Omnidirectional Metamaterial MIMO Antenna for Vehicular Radar

In this paper, a gain-enhanced wideband multiple-input-multiple-output (MIMO) antenna with high isolation and quasi-omnidirectional radiation is proposed. It is a hexagonal structure and includes six identical end-fire log-periodic dipole antenna (LPDA) elements. These antenna elements are distributed in the same plane and uniformly placed in a rotating arrangement with an angle difference of 60°, and then are suspended over a large metallic plate (LMP). To enhance the wideband gain, different metasurface (MS) lens with high refractive index is deployed around the end-fire log-periodic dipole. The uniform MS lens makes electromagnetic waves deflect toward the array axis of the LPDA, whereas the gradient MS lens could form focused plane electromagnetic waves in the end-fire direction. Furthermore, these antenna elements are isolated with a complementary split ring resonator (CSRR)-based electromagnetic band-gap (EBG) structure owing to its wide bandstop frequency and small-size characteristics. To validate the design concept, the prototype is fabricated and measured. The measured -10-dB impedance bandwidth covers 2.85-10.9 GHz (FBW 117.1%) and the gain varies from 10.37 to 14.82 dBi. Moreover, high isolation of better than 22.4 dB and low envelope correlation coefficient (ECC) of less than -62.3 dB are achieved between antenna elements. The proposed wideband MIMO antenna could be suitable for vehicular radar.

Inverse Scattering by Perfectly Electric Conducting (PEC) Rough Surfaces: An Equivalent Model With Line Sources

This paper presents a new method for the reconstruction of the perfectly electric conducting (PEC) rough surface profiles by utilizing electromagnetic waves. The inaccessible rough surface is illuminated by a tapered plane electromagnetic wave and the scattered field data are measured on a certain number of points above the surface under test. The method for the inverse electromagnetic imaging problem is based on a special representation of the scattered field in terms of a finite number of fictitious discrete line sources located along a plane below the rough surface. The current densities of these fictitious sources are obtained through the regularized solution of an ill-posed problem. Then, it is shown that the image of the rough surface can be directly retrieved by seeking the points in the space where the tangential component of the total electric field vanishes. Alternatively, a much more rigorous iterative method based on a regularized Newton algorithm is also presented. A comprehensive numerical analysis is provided to demonstrate the feasibility of the presented approach. In this context, the quantitative successes of both approaches are interpreted by considering a very sensitive ℓ <sub xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">2</sub> -norm based error function between the actual and the reconstructed surface profiles. Regarding different scattering scenarios taken into account, the error values obtained for satisfactory reconstructions are generally in the range of 10% - 30% for both methods. It is also shown that the presented algorithms are capable of reconstructing the rough surfaces which oscillate for every λ horizontally and have a peak to peak variation 0.5λ at most.

Simulation of Microwave Remote Sensing of the Ocean

The paper considers simulation of microwave remote sensing of the ocean. The direct and inverse problems of diffraction of a plane electromagnetic wave on a periodic inhomogeneous layer of finite thickness are considered. The computer program is developed, that allows to model the process of active and passive radiometry of the free surface or of the near-surface layer of the ocean. The program is validated by comparison with the analytical result for the case of a periodically repeating planar layered structure. High accuracy of calculations is shown. The results of a number of calculations for the needs of passive and active radiometry of the surface and of the medium consisting of layers with sinusoidal boundaries are presented.

Focused Planar Electromagnetic Waves for Enhanced Near-Field Microwave Imaging With Verification Using Tapered Gradient-Index Lens Antenna

Focused Planar Electromagnetic Waves for Enhanced Near-Field Microwave Imaging With Verification Using Tapered Gradient-Index Lens Antenna

The radiation of a spin-free particle in the field of a plane electromagnetic wave

In this paper, we obtained a solution for the equation of motion of a charged spinless particle in the field of a plane electromagnetic wave. Relativistic expressions for the cross section of Compton scattering by a charged particle of spin 0 interacting with the field of a plane electromagnetic wave are calculated. Numerical simulation of the total probability of radiation as the function of the electromagnetic wave amplitude is carried out. The radiation probability is found to be consistent with the total cross section for Compton scattering by a charged particle of spin 0.

Features of Scattering of a Plane Electromagnetic Wave on a Conductive Ball

The phenomenon of scattering of a plane electromagnetic wave on a nonmagnetoactive conductive ball is studied. The dispersion of electromagnetic waves inside the ball material is taken into account. A special case of that phenomenon (the radius of the ball is much smaller than the wavelength of the scattered wave) lies in the basis of the work of a spaser, which can have a wide range of important practical applications.