V. Dmitriev

Microwave Frequency Selective Surfaces with High Q-Factor Resonance and Polarization Insensitivity

Analysis of frequency selective surfaces with high Q-factor resonance and polarization insensitivity is the aim of this work. Two new array configurations are suggested, which support the trapped-mode regime. The arrays were optimized in order to obtain the highest Q-factor by varying some of their geometrical and physical parameters. Theoretical results are presented and discussed.

Broadband L-Probe Fed Patch Antenna Combined With Passive Loop Elements

A new broadband L-probe fed rectangular patch antenna electromagnetically coupled to parasitic loop elements is presented. The proposed antenna is analyzed numerically using the moment-method-based electromagnetic simulation (IE3D) and high-frequency structure simulation (HFSS) softwares. The calculated results are in a good agreement with measured data. The impedance bandwidth of a prototype manufactured using a dielectric substrate with the relative permittivity epsir = 2.55 is about 15%

PSO-GPU: accelerating particle swarm optimization in CUDA-based graphics processing units

This work presents a PSO implemention in CUDA architecture, aiming to speed up the algorithm on problems which has large amounts of data. PSO-GPU algorithm was designed to customization, in order to adapt for any problem that can be solved by a PSO algorithm. By implementing PSO using CUDA architecture, each processing core of the GPU will be responsible for a portion of the overall processing operation, where each one of these pieces are handled and executed in a massive parallel enviroment, opening the possibility for solving problems that require a large processing load in considerably less time. In order to evaluate the performance of PSO-GPU algorithm two functions were used, both global optimization problems, where without constraints (Griewank function) and other considering constraints, the Welded Beam Design (WBD).

Comparative analysis of circular and triangular gold nanodisks for field enhancement applications

In this paper, we present a quantitative comparison of circular and triangular gold nanodisks with the same length and thickness. The method of moments is used to solve numerically the scattering problem. With this model, we investigate the spatial near field distribution, spectral response, far field diagrams, and bandwidth wavelength of these particles. Our results show that the resonant wavelength and the near field enhancement and confinement of the triangular particle are larger than those for the circular particle, but the resonance bandwidth and scattering cross section of the triangular particle are smaller.

Fractal spiral monopoles: theoretical analysis and bandwidth optimization

Spiral antennas are characterized by low resonant frequencies and broadband matching for high frequencies. We present in this work a theoretical analysis and optimization of a special type of spiral antenna, namely the fractal spiral monopole (FSM). In the low frequencies in the range 0<L//spl lambda/<1 (L is the height of the monopole and /spl lambda/ the wavelength), variation of the resonant frequencies in function of the monopoles dimensions was investigated. In the high frequencies in the range 0<L//spl lambda/<3, the monopoles dimensions were optimized in order to obtain broadband matching. The method of moments (MoM) was used for calculations.

Analysis of surface plasmon resonance sensor coupled to periodic array of gold nanoparticles

This paper presents a theoretical analysis of a surface plasmon resonance sensor coupled to a periodic array of spherical gold nanoparticles (AuNps). The sensor is in the Kretschmann configuration and composed by five layers: prism, thin gold film, dielectric insulator, array of AuNps and air. The AuNps layer is modeled with an effective permittivity by the Maxwell-Garnett mixing formula, and the wave propagation is analyzed using a generalized reflection coefficient. The results are presented in terms of reflectivity and modal field distributions for different thickness of the layers and geometry of the AuNps array.

Development of computational 3D MoM algorithm for nanoplasmonics

In this paper, we present an algorithm for full-wave electromagnetic analysis of nanoplasmonic structures. We use the three-dimensional Method of Moments to solve the electric field integral equation. The computational algorithm is developed in the language C. As examples of application of the code, the problems of scattering from a nanosphere and a rectangular nanorod are analyzed. The calculated characteristics are the near field distribution and the spectral response of these nanoparticles. The convergence of the method for different discretization sizes is also discussed.

Application of particle swarm optimization to ultra-wideband multistatic radar used for protection of indoor environment

A numeric simulation of a multistatic radar using the finite-difference time-domain (FDTD) method and particle swarm optimization (PSO) is implemented in order to localize an intruder inside a laboratory complex. In order to obtain high resolution and to avoid interference with other radiosystems, the radar operates with ultra-wideband pulses and spectral spreading. The transmitted signal has a spectral peak at 1 GHz and the bandwidth of approximately 1 GHz. To estimate the location of the target, two transmitters and nine receivers are used. The transmitters operate in TDM mode in order to avoid interference between them.

Modeling and analysis of lightning effects in OPGW cables using the ADI-FDTD method

Abstract Current density distribution in optical ground wire cables hit by lightning strokes is numerically calculated and studied in time domain. For this analysis, two models for current source were considered, since atmospheric discharge has two major components which usually damage more severely the cable: the long and short duration current components. The analysis is performed by employing the Alternating Direction Implicit Finite-Difference Time-Domain (ADI-FDTD) method, which the presented formulation was especially developed by the authors to analyze this phenomenon. The convolutional perfectly matched layer (CPML) technique adapted for the ADI method, called ADI-CPML, is also developed in this work for truncating the ADI-FDTD computational domain.

Resonant properties, of modified triangular plasmonic nanoparticles with higher field concentration

In this paper, we present an analysis of the resonant response of modified triangular metallic nanoparticles with polynomial sides. The particles are illuminated by an incident plane wave and the method of moments is used to solve numerically the electromagnetic scattering problem. We investigate spectral response and near field distribution in function of the length and polynomial order of the nanoparticles. Our results show that in the analyzed wavelength range (0.5-1.8) μm these particles possess smaller number of resonances and their resonant wavelengths, near field enhancement and field confinement are higher than those of the conventional triangular particle with linear sides.