Nataliya P. Yashina

Bio: Nataliya P. Yashina is an academic researcher from National Academy of Sciences of Ukraine. The author has contributed to research in topics: Boundary value problem & Diffraction. The author has an hindex of 10, co-authored 65 publications receiving 333 citations. Previous affiliations of Nataliya P. Yashina include Gebze Institute of Technology & Moscow Aviation Institute.

Modeling and analysis of transient processes in open resonant structures : new methods and techniques

Abstract: Preface.- Numerical analysis of transient processes: fundamental results of the theory, methods and problems. Introduction. Main equations and fundamental results of the theory. Methods of solving initial boundary problems on the basis of space-time representations. Time domain methods.- Waveguides and periodic structures: exact 'absorbing' conditions on virtual boundaries in cross section of a regular wave guiding structures. Introduction. Compact waveguide units. 2-D scalar problems in cylindrical coordinates. Vector problems of the theory of open waveguide resonators. Problems of the electromagnetic theory of gratings.- Compact inhomogeneities in free space: virtual coordinate boundaries in scalar and vector problems of wave scattering theory. Introduction. Exact conditions for artificial boundaries in cylindrical (polar) coordinates. Exact conditions for artificial boundaries in Cartesian coordinates. Vector problems: spherical coordinates. Axially symmetric problems: spherical and cylindrical coordinates.- The simplest modifications of the 'Exact ABCs' approach and the associated numerical tests. Introduction. Radiators with infinite flanges. Wave radiation from a plane-parallel waveguide of arbitrary aperture. The problems of strong and remote field sources. Evolutionary basis of outgoing waves in the domains LQ with homogeneous and inhomogeneous filling. Numerical tests of the new exact conditions.- Transform operators in space of signal's evolutionary basis: a time domain analogue of generalized scattering-matrix method. Introduction. Evolutionary signal basis and transform operators. Canonical problems of time domain. Algorithms for calculating transient characteristics of resonant inhomogeneities. Signals in the floquet channel: the transform operators and some canonical initial boundary-value problems.- Open periodic resonators and waveguides: novel results in electromagnetic theory of gratings. Introduction. Essential qualitative results inthe spectral theory of gratings. Dynamic patterns of spectral points in the frequency domain. Gratings in transient wave fields. Establishing of regularities. Pulse deformations by free propagation in regular section of the floquet channels.- Model synthesis of resonance quasi-optical devices: dispersive open resonators, absorbing coatings, pattern-forming structures. Introduction. Model synthesis of structures including grating dispersive elements (Frequency Domain). Inverse problems in electromagnetic theory of gratings (Frequency domain). Open dispersive resonators. Transient processes in the near zone of pulsed waves radiators.- References.- Appendix A.

Surface resonances of metal stripe grating on the plane boundary of metamaterial

Abstract: The paper is devoted to the study of the interaction of the electromagnetic waves with the structure composed of perfectly conducting strip grating, situated on the plane boundary of metamaterial with effective permittivity, depending on the frequency of the wave of excitation. The rigorous solution to the relevant diffraction boundary value problem is developed. The extensive numerical experiments, performed with a help of corresponding algorithm constructed, allowed to establish several regularities in the complicated process of interaction of electromagnetic waves with grating on dispersive metamaterial. The efficient association of analytical and numerical study has provided the understanding of the nature of resonant phenomena appearing in this process.

C-method: several aspects of spectral theory of gratings

Abstract: The goal of the present paper is two folded. The first, the methodological one, is the complementation of well established in diffraction theory of gratings C method with certain elements of spectral theory and the development of interactive numerical algorithm that made feed back conjunction between diffraction and spectral problems. As a natural result the second goal appeared: the appearing of such tool for numerical experiments resulted in profound qualitative and quantitative study of rather peculiar phenomena in resonant scattering from periodic surface. Special attention has been paid to the investigation of electromagnetic waves diffraction from periodic boundaries of material with single and double negative parameters.

Explicit Conditions for Virtual Boundaries in Initial Boundary Value Problems in the Theory of Wave Scattering

Abstract: This paper deals with the problem of finding a correct way of restricting the computational domain in the FDTD-method in its application to the analysis of transient wave processes in infinite homogeneous regions containing compact inhomogeneities. The formulation of the explicit ABCs (Absorbing Boundary Conditions) in such a way that they do not distort the physical model simulated by the mathematics, and the incorporation of these ABCs in the computational scheme form the basis of the approach presented here. A number of numerical results are given, illustrating in particular the performance of the exact ABCs in comparison with lower order approximations.

Radiation from surface with periodic boundary of metamaterials excited by a current

Abstract: The rigorous modeling and analysis of electromagnetic wave transformation and radiation from the periodic boundary of metamaterial are presented. The nature of the phenomenon of resonant radiation and the influence of various parameters on it are investigated. The study is carried out with the objective of potential applications to antenna design. Simulated results show that very high directivity can be obtained and that beam steering can be achieved by adjusting proper parameters.

Plasmon resonances of a gold nanostar.

Abstract: Using the finite-difference time-domain method, we show that the plasmons of a nanostar result from hybridization of plasmons of the core and tips of the nanoparticle. The nanostar core serves as a nanoscale antenna, dramatically increasing the excitation cross section and the electromagnetic field enhancements of the tip plasmons. Our analysis demonstrates that the plasmon hybridization picture can be combined with numerical approaches to interpret the physical origin of the plasmons of highly complex nanostructures.

Ultra-wideband, short-pulse electromagnetics 2

Abstract: PULSE GENERATION AND DETECTION: Semiconductor Switching: The Time Evolution of Photonic Crystal Bandgaps (K. Agi et al.). General: Ultrawideband Pulser Technology (D.M. Parkes). ANTENNAS: Impulse Radiating Antennas: Transient Fields of Rectangular Aperture Antennas (S.P. Sulkin). Reflector Impulse Radiating Antennas: Temporal and Spectral Radiation on Boresight of a Reflector Type of Impulse Radiating Antenna (IRA) (D.V. Giri, C.E. Baum). Lens Impulse Radiating Antennas and TEM Horns: Design of the Low-Frequency Compensation of an Extreme-Bandwidth TEM Horn and Lens IRA (M.H. Vogel). Arrays: Transient Arrays (C.E> Baum). General: Some Basic Properties of Antennas Associated with Ultra-wideband Radiation (S.N. Samaddar, E.L. Mokole). PULSE PROPOGATION AND GUIDEANCE: Transient Dielectric Coefficient and Conductance in Dielectric Media in Nonstationary Fields (A. Gutman). SCATTERING THEORY, COMPUTATION, AND MEASUREMENTS: Early Time Signature Analysis of Dielectric Targets Using UWB Radar (S. Cloude et al.). SIGNAL PROCESSING: Time-Frequency Analysis: Feature Extraction from Electromagnetic Backscattered Data Using Joint Time-Frequency Processing (L.C. Trintinalia, H. Ling). Spectral Techniques: The E-Pulse Technique for Dispersive Scatterers (S. Primak et al.). Probabilistic Considerations: Robust Target Identification Using a Generalized Likelihood Ratio Test (J.E. Mooney et al.). General: Error Correction in Transient Electromagnetic Field Measurements Using Deconvolution Techniques (J-Z. Bao et al.). BROADBAND ELECTRONIC SYSTEMS AND COMPONENTS: Systems and Components: Ultra-wideband Sources and Antennas: Present Technology, Future Challenges (W.D. Prather et al.). Ultra-Wideband Radars: Dense Media Penetrating Radar (K. Min, M. Willis, Jr.). Polarimetric Ultra-wideband Radars: Polarimetry in Ultra-wideband Interferometric SEnsing and Imaging (W-M. Boerner, J.S. Verdi). BURIED TARGETS: Analytic Methods for Pulsed Signal Interaction with Layered, Lossy Soil Environments and Buried Objects (L.B. Felsen). 41 additional articles. Index.

Research Progress in Reversed Cherenkov Radiation in Double-Negative Metamaterials

Abstract: We review the research progress in reversed Cherenkov radiation in double-negative metamaterials (DNMs) starting from the first experimental verification of the DNMs reported in 2001, including theories, numerical computation and simulation and experiments. We also discuss the potential applications to particle detectors and highpower microwave or millimeter-wave devices, including the oscillators and amplifiers, and the formidable challenges needed to be resolved before the benefits of using such artificial materials can be harvested. Corresponding author: Z. Y. Duan (zhyduan@uestc.edu.cn).