Simulation Of Electromagnetic Wave Propagation Research Articles

Optimised correction polynomial functions for the Flux Reconstruction method in time-harmonic electromagnetism

The Flux Reconstruction (FR) method is classically used in the Computational Fluid Dynamics field. However, its use for the simulation of electromagnetic wave propagation is not as developed yet. Following on from the development of a priori error estimates for the 1D wave equations, we introduce optimisation problems to allow an adaptation of the FR correction polynomial functions to the discretisation parameters. Showing notable accuracy gains in 1D, especially in the preasymptotic regime, we generalise this procedure to the 3D Maxwell’s equations, leading to similar interesting possibilities to reduce the computational cost for a given accuracy.

Transient Simulation of Electromagnetic Wave Propagation in Plasma Based on Dynamic Drude Model

Transient Simulation of Electromagnetic Wave Propagation in Plasma Based on Dynamic Drude Model

Design Simulation of Multilayer Structures for the Development of Biosensor Based on Transverse Matrix Method

Simulation of electromagnetic wave propagation on layered metal-dielectric structures using analytical methods is a study that continues to be developed because it involves strict mathematical equations with exact results. In this study, the transfer matrix method was developed to analyze the dielectric-metal-metal-dielectric structure through the reflection profile. The emergence of the Surface Plasmons Resonance (SPR) phenomenon causes a minimum reflectance whose changes are analyzed through variations in optical and physical parameters. The simulation shows that the minimum reflectance angle occurs at an angle , indicating the existence of the SPR phenomenon in the condition . The choice of metal materials, namely gold and silver, resulted in a shift in the reflectance curve, and an increase in the thickness of the adhesive layer caused a shift in the reflectance curve towards a smaller angle. Changes in the refractive index of the upper dielectric material are important for biosensor development, namely a shift in the reflectance curve with a linear response at the interval of refractive index .

Realistic simulation of GPR for landmine and IED detection including antenna models, soil dispersion and heterogeneity

AbstractGround‐penetrating radar is an effective tool for detecting landmines and improvised explosive devices, but its performance is strongly influenced by subsurface properties as well as the characteristics of the target. To complement or replace labour‐intensive experiments on test sites, cost‐efficient electromagnetic wave propagation simulations using the finite‐difference time‐domain method are being increasingly used. However, to obtain realistic synthetic data, accurate modelling of signal alteration caused by dispersion, scattering from soil material, target contrast, shape, and inner setup, as well as the coupling effects of the antenna to the ground is required. In this study, we present a detailed three‐dimensional model of a shielded ground‐penetrating radar antenna applied to various scenarios containing metallic and non‐metallic targets buried in different soils. The frequency‐dependent intrinsic material properties of soil samples were measured with the coaxial transmission‐line technique, while a discrete random media was used to implement the heterogeneity of a gravel based on its grain‐size distribution. Our simulations show very good agreement with experimental validation data collected under controlled conditions. We accurately reproduce the amplitude, frequency, and phase of target signals, the subsurface background noise, antenna crosstalk and associated interference with target signals, and the effect of antenna elevation. The approach allows for a systematic investigation of the effects of soil, target, and sensor properties on detection performance, providing insight into novel and complex ground‐penetrating radar scenarios and the potential for a wide range of simulation possibilities for demining with ground‐penetrating radar. These investigations have the potential to improve the safety and effectiveness of landmine and improvised explosive device detection in the future, such as building a database for training deminers or developing automatic signal pattern recognition algorithms.

Accelerating Electromagnetic Field Simulations Based on Memory-Optimized CPML-FDTD with OpenACC

Although GPUs can offer higher computing power at low power consumption, their low-level programming can be relatively complex and consume programming time. For this reason, directive-based alternatives such as OpenACC could be used to specify high-level parallelism without original code modification, giving very accurate results. Nevertheless, in the FDTD method, absorbing boundary conditions are commonly used. The key to successful performance is correctly implementing the boundary conditions that play an essential role in memory use. This work accelerates the simulations of electromagnetic wave propagation that solve the Maxwell curl equations by FDTD using CMPL boundary in TE mode using OpenACC directives. A gain of acceleration optimizing the use of memory is shows, checking the loops intensities, and the use of single precision to improve the performance is also analyzed, producing an acceleration of around 5X for double precision and 11X for single precision respectively, comparing with the serial vectorized version, without introducing errors in long-term simulations. The scenarios of simulation established are common of interest and are solved at different frequencies supported by a Mid-range cards GeForce RTX 3060 and Titan RTX.

Simulation of Electromagnetic Wave Propagation in Plasma Under High-Power Microwave Illumination

This letter focuses on the propagation characteristics of the electromagnetic wave in the plasma under high-power microwave (HPM) illumination. A multiphysical method coupling the electromagnetic field and plasma fluid field is proposed as the dynamic Drude model. The differences between the method based on dynamic Drude model and traditional static Drude model are discussed theoretically for the first time. Unlike the static Drude model, the dynamic Drude model fully considers the motion of electrons in plasma driven by electromagnetic field. Numerical examples demonstrate that both the dynamic Drude model-based and static Drude model-based method are consistent with each other under low power microwave illumination, where the plasma can be considered as a static media. While under HPM illumination, electrons gradually gather together to hinder the propagation of electromagnetic waves. Hence, the proposed dynamic Drude model is more logical to analyze the characteristics of electromagnetic wave in plasma than the traditional static Drude model under HPM illumination.

Performance Evaluation of Electromagnetic Shield Constructed from Open-Cell Metal Foam Based on Sphere Functions

This study evaluates the performance of a model of open-cell metal foams generated by sphere functions. To this end, an electromagnetic shield constructed from the model was inserted between two horn antennas in an electromagnetic wave propagation simulation. The foam-hole diameter in the electromagnetic shield model was varied as d = 2.5 and 5.0 mm, and the frequency of the electromagnetic waves was varied from 3 to 13 GHz. In the numerical experiments of shield effectiveness, the shields with foam holes of both diameters attenuated the electromagnetic waves across the studied frequency range. The shield effectiveness was enhanced at low frequencies and in the shield with smaller hole diameter.

О применении конечно-разностной аппроксимации Паде псевдодифференциального параболического уравнения в задаче тропосферного распространения радиоволн

Рассматривается задача численного моделирования распространения электромагнитных волн в неоднородной тропосфере на основе широкоугольных обобщений метода параболического уравнения. Используется конечно-разностная аппроксимация Паде оператора распространения. Существенно, что в предлагаемом подходе указанная аппроксимация осуществляется одновременно по продольной и поперечной координатам. При этом допускается моделирование произвольного коэффициента преломления тропосферы. Метод не накладывает ограничений на максимальный угол распространения. Для различных условий распространения радиоволн проведено сравнение с методом расщепления Фурье и методом геометрической теории дифракции. Показаны преимущества предлагаемого подхода. This paper is devoted to the numerical simulation of electromagnetic wave propagation in an inhomogeneous troposphere. The study is based on the wide-angle generalizations of the parabolic wave equation. The finite-difference Padé approximation is used to approximate the propagation operator. It is important that, within the proposed approach, the Padé approximation is carried out simultaneously along with the longitudinal and transverse coordinates. At the same time, the proposed approach gives an opportunity to model an arbitrary tropospheric refractive index. The method does not impose restrictions on the maximum propagation angle. The comparison with the split-step Fourier method and the geometric theory of diffraction is discussed. The advantages of the proposed approach are shown.

Modelling and experimental validation of EM wave propagation due to PDs in XLPE cables

Monitoring of electromagnetic (EM) waves due to partial discharge (PD) is a promising tool for condition monitoring of cables. This study presents the development of a modelling scheme for simulation of EM wave propagation due to PDs occurring at cavities in the cross-linked polyethylene (XLPE) insulation. Simulation models for generation and propagation of PD pulses through the cable geometry are developed. A finite element method (FEM)-based model is developed to simulate the PD current along cylindrical voids in the cable insulation. The initial fields due to the PD currents in the voids are simulated by an FEM model. The propagated EM fields inside and outside the cable surface due to PD's occurring inside the voids are analysed by a finite-difference time-domain model. The analysis of propagated EM fields due to a Gaussian-shaped PD pulse identifies the dominant components of propagated electric and magnetic fields along the cable geometry. Furthermore, the propagated EM fields at the cable sheath due to different void dimensions are simulated and experimental validation of the propagated magnetic field is conducted with measurement by an high-frequency current transformer sensor installed around an earth wire from the sheath of an 11 kV XLPE cable.

Simulation of EM wave propagation along a femtosecond laser plasma filament

Abstract The propagation of electromagnetic (EM) wave along a plasma filament induced by the sufficiently intense femtosecond laser pulse is studied with the commercial simulation software XFDTD. The simulated results show that the EM wave can propagate along the plasma filament, with the electric field enhanced out of the waveguide and attenuated in the waveguide. Besides, we can conclude that the relative direction between the plasma filament and the electric field can influence the guiding performance of the plasma filament. Furthermore, a maximum EM wave intensity enhancement more than threefold the free space propagation is realized. The research results imply that the laser-induced plasma filament can provide efficient transmission of the EM wave energy.

Evaluation of dielectric materials properties using microwave enhanced metamaterials sensor

The paper proposes the use a metamaterial structure for improving the transmission properties of open waveguide probe, developing a frequency selective sensor in microwave frequency X band sensitive to changing of properties of investigated dielectric material. This assembly can be used for properties of dielectric material investigation. The numerical simulations of electromagnetic wave propagation in rectangular waveguide with metamaterial structure were performed using the FEM and FDTD. The numerical results were proved with experiments, testing two types of biological materials.

Temperature induced in human organs due to near-field and far-field electromagnetic exposure effects

The main biological effect from exposure to electromagnetic (EM) radiation is a temperature rise in the human body and its sensitive organs, which results from absorbing electromagnetic field (EMF) power. EM near-field and far-field sources, which have different operating frequencies and exposure distances, result in different EMF distribution patterns and EMF power absorptions by the human body. Actually, the severity of the physiological effect can occur with small temperature increases in the sensitive organs. However, the EM absorption characteristics and the temperature increase distribution resulting from different field radiation patterns from EM sources are not well established. To adequately explain the biological effects that are associated with the EMF energy absorption, a systematic study of different EMF distribution patterns and how they interact with body tissue is needed. This study considers the computationally determined specific absorption rate (SAR) and the heat transfer in a heterogeneous human torso model with internal organs exposed to near-field and far-field EM radiations at different frequencies. The electric field, SAR, and the temperature distributions in various organs during exposure to EMFs are obtained through the numerical simulation of EM wave propagation and an unsteady bioheat transfer model. The findings indicate that the field radiation pattern and the operating frequency of an EM source significantly influence the electric field, the SAR, and the temperature distribution in each organ. Moreover, the tissue’s dielectric properties also affect the temperature distribution patterns within the body tissue. These findings enable researchers to more accurately determine the exposure limits for the power output of wireless transmitters, and the distance that they should remain from the humans.

Terahertz Channel Model and Link Budget Analysis for Intrabody Nanoscale Communication.

Nanosized devices operating inside the human body open up new prospects in the healthcare domain. Invivo wireless nanosensor networks (iWNSNs) will result in a plethora of applications ranging from intrabody health-monitoring to drug-delivery systems. With the development of miniature plasmonic signal sources, antennas, and detectors, wireless communications among intrabody nanodevices will expectedly be enabled at both the terahertz band (0.1-10 THz) as well as optical frequencies (400-750 THz). This result motivates the analysis of the phenomena affecting the propagation of electromagnetic signals inside the human body. In this paper, a rigorous channel model for intrabody communication in iWNSNs is developed. The total path loss is computed by taking into account the combined effect of the spreading of the propagating wave, molecular absorption from human tissues, as well as scattering from both small and large body particles. The analytical results are validated by means of electromagnetic wave propagation simulations. Moreover, this paper provides the first framework necessitated for conducting link budget analysis between nanodevices operating within the human body. This analysis is performed by taking into account the transmitter power, medium path loss, and receiver sensitivity, where both the THz and photonic devices are considered. The overall attenuation model of intrabody THz and optical frequency propagation facilitates the accurate design and practical deployment of iWNSNs.

Efficient Simulation of Electromagnetic Wave Propagation in Complex Shaped Domain by Hybrid Method of FDTD and MTDM Based on Interpolating Moving Least Squares Method

To utilize the advantages of both finite-difference time-domain (FDTD) method and meshless time-domain method (MTDM) based on the interpolating moving least squares method, a hybrid method of FDTD and MTDM has been proposed for electromagnetic wave propagation simulations in complex shaped domains. In this method, FDTD is employed in rectangle domains, and MTDM is used in other kinds of domains. Numerical experiments show that the electric field is smoothly propagated, containing connection parts of domains calculated by FDTD and MTDM. In addition, the convergence value of amplification/damping rate of a hybrid method is almost the same as that of FDTD, and the accuracy of the hybrid method is better than that of FDTD for the case where the number of nodes is relatively small. Furthermore, the computation time of the hybrid method is less than that of MTDM.

Optimal non-dissipative discontinuous Galerkin methods for Maxwell’s equations in Drude metamaterials

Simulation of electromagnetic wave propagation in metamaterials leads to more complicated time domain Maxwell’s equations than the standard Maxwell’s equations in free space. In this paper, we develop and analyze a non-dissipative discontinuous Galerkin (DG) method for solving the Maxwell’s equations in Drude metamaterials. Previous discontinuous Galerkin methods in the literature for electromagnetic wave propagation in metamaterials were either non-dissipative but sub-optimal, or dissipative and optimal. Our method uses a different and simple choice of numerical fluxes, achieving provable non-dissipative stability and optimal error estimates simultaneously. We prove the stability and optimal error estimates for both semi- and fully discrete DG schemes, with the leap-frog time discretization for the fully discrete case. Numerical results are given to demonstrate that the DG method can solve metamaterial Maxwell’s equations effectively.

Electromagnetic waves in media with permittivity dispersion

A technique for the numerical simulation of electromagnetic wave propagation in materials with permittivity depending on the frequency is presented. The technique is based on numerical solutions of Maxwell equations with additional integral components in the bias current density. The technique to calculate the bias current density in dispersive media is represented and the corresponding modification of finite-difference scheme for Maxwell equations developed earlier is carried out. The electromagnetic pulse propagation in solid-fuel power systems is calculated.

Electromagnetic Modeling of Human Body Using High Performance Computing

Realistic simulation of electromagnetic wave propagation in the actual human body can expedite the investigation of the phenomenon of harvesting implanted devices using wireless powering coupled from external sources. The parallel electromagnetics code suite ACE3P developed at SLAC National Accelerator Laboratory is based on the finite element method for high fidelity accelerator simulation, which can be enhanced to model electromagnetic wave propagation in the human body. Starting with a CAD model of a human phantom that is characterized by a number of tissues, a finite element mesh representing the complex geometries of the individual tissues is built for simulation. Employing an optimal power source with a specific pattern of field distribution, the propagation and focusing of electromagnetic waves in the phantom has been demonstrated. Substantial speedup of the simulation is achieved by using multiple compute cores on supercomputers.

New Software Tool (GO+UTD) for Visualization of Wave Propagation [Testing Ourselves

A MATLAB-based tool, GO+UTD, is presented with a user-friendly graphical user interface (GUI) for the simulation of electromagnetic wave propagation and diffraction effects over variable terrain by using the geometrical optics (GO) and the uniform theory of diffraction (UTD) techniques. The theoretical background, structure, capabilities, and limitations of the tool are discussed in detail in this article. The validation of GO+UTD is performed via numerical comparisons with the parabolic equation toolbox (PETOOL). GO+UTD is a freely available tool that can be used for research and educational purposes to investigate wave phenomena with special emphasis on diffraction effects. It can be downloaded at http://www.ee.hacettepe.edu.tr/~ozlem/.

A Performance Study of CUDA UVM versus Manual Optimizations in a Real-World Setup: Application to a Monte Carlo Wave-Particle Event-Based Interaction Model

The performance of a Monte Carlo model for the simulation of electromagnetic wave propagation in particle-filled atmospheres has been conducted for different CUDA versions and design approaches. The proposed algorithm exhibits a high degree of parallelism, which allows favorable implementation in a GPU. Practical implementation aspects of the model have been also explained and their impact assessed, such as the use of the different types of memories present in a GPU. A number of setups have been chosen in order to compare performance for manually optimized versus Unified Virtual Memory (UVM) implementations for different CUDA versions. Features and relative performance impact of the different options have been discussed, extracting practical hints and rules useful to speed up CUDA programs.

GPR investigation of the strengthening system of a historic masonry tower

In this paper the condition assessment of the strengthening system of a masonry tower was carried out by the GPR method. The study provided unique experimental data acquired during measurements of the reinforced concrete frame embedded in masonry walls. Conducted numerical and experimental investigations were focused on the phenomenon of the diffraction–refraction scattering of the electromagnetic energy. A hyperbola resulting from the diffraction of the electromagnetic wave by a steel rod revealed a clear refraction point at the boundary between concrete and the brick wall. A novel procedure for determining the boundary between two media, where one of them contains a circular inclusion, was developed. A system of equations describing the refracted hyperbolic diffraction curve was derived. The study demonstrated that the identification of the actual width of the reinforced concrete strengthening was possible analysing refracted waves previously diffracted on bars, where the point of refraction indicated the boundary between media. Numerical simulations of electromagnetic wave propagation were carried out to enhance the interpretation of results of GPR surveys in the complex masonry structure strengthened by reinforced concrete. The particular interest was paid on characteristics of wave patterns at the boundary between media having different electrical properties. The obtained numerical and experimental results revealed the high usefulness of the GPR method in the diagnosis of wall structures made with different materials.