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Showing papers on "Computational electromagnetics published in 2017"



Book
30 May 2017
TL;DR: This book provides intuitive solutions to electromagnetic problems by using the Partial Element Equivalent Circuit (PEEC) method with an introduction to circuit analysis techniques, laws, and frequency and time domain analyses.
Abstract: This book provides intuitive solutions to electromagnetic problems by using the Partial Element Equivalent Circuit (PEEC) method. This book begins with an introduction to circuit analysis techniques, laws, and frequency and time domain analyses. The authors also treat Maxwell's equations, capacitance computations, and inductance computations through the lens of the PEEC method. Next, readers learn to build PEEC models in various forms: equivalent circuit models, non-orthogonal PEEC models, skin-effect models, PEEC models for dielectrics, incident and radiate field models, and scattering PEEC models. The book concludes by considering issues like stability and passivity, and includes five appendices some with formulas for partial elements.

161 citations


Journal ArticleDOI
TL;DR: An edge-based finite element method for 3D CSEM modeling which is effective in modeling complex geometry such as bathymetry and capable of dealing with anisotropic conductivity is developed.

66 citations


Journal ArticleDOI
TL;DR: In this article, the authors presented electromagnetic modeling and analysis of the detent force in a permanent magnet linear synchronous machine (PMLSM) according to auxiliary teeth configuration and derived analytical solutions for magnetic fields generated by PMs.
Abstract: This paper presents electromagnetic modeling and analysis of the detent force in a permanent magnet linear synchronous machine (PMLSM) according to auxiliary teeth configuration. Analytical solutions for magnetic fields generated by PMs are derived based on the Maxwell equation in terms of a 2-D Cartesian coordinate system. The magnetic vector potential of each subdomain (PM, air-gap, slot, and end region) is derived, and the field solution is obtained by applying the boundary and interface conditions between the subdomains. Based on the analytical solution, the magnetic force is derived by using the Maxwell stress tensor. All the analytical results were extensively validated using nonlinear finite-element analysis and experimental results. Using the proposed method, we investigated the influence of the machine parameters on the detent force. Therefore, the proposed method can be very useful in the initial design and optimization process of PMLSM for detent force analysis.

42 citations


Journal ArticleDOI
TL;DR: The interior penalty fluxes corresponding to different types of boundary conditions which are commonly used in electromagnetic modeling are developed to construct the IPDG-THE AUTHORS system in local elements to demonstrate the validity, versatility, and potential of the proposed method in 3-D electromagnetic problems modeling.
Abstract: Built on the vector wave equation, an interior penalty discontinuous Galerkin time domain (IPDG-WE) method is presented for 3-D real-life electromagnetic modeling in this paper. We develop the interior penalty fluxes corresponding to different types of boundary conditions which are commonly used in electromagnetic modeling to construct the IPDG-WE system in local elements. In addition, to model the incident wave excitation, the total-field/scattered-field approach is incorporated into the proposed method. The stability of the IPDG-WE method is studied analytically and demonstrated numerically. We also compare the performance between wave equation-based finite-element time-domain method, the Maxwell’s equation-based discontinuous Galerkin time-domain method, and the proposed method, both in CPU time and memory usage, which demonstrates that the IPDG-WE method is very competitive among time-domain solvers. Besides, the presented method shows good characteristics including the energy conservation and the optimal convergence rate of $O( {h^{p+1}})$ . Numerical examples are presented to illustrate the validity, versatility, and potential of the proposed method in 3-D electromagnetic problems modeling.

34 citations


Journal ArticleDOI
TL;DR: In this paper, an analytical procedure for the preliminary design of a high-speed ferrite-based brushless dc machine (HS-BLDC) has been proposed, in order to take into account their mutual influence in the definition of the geometry of the electrical machine.
Abstract: In this paper an analytical procedure for the preliminary design of a high-speed ferrite-based brushless dc machine (HS-BLDC) has been proposed. In particular, mechanical and electromagnetic modeling have been developed in order to take into account their mutual influence in the definition of the geometry of the electrical machine. In addition, suitable design targets have been imposed in accordance with electric vehicle application requirements. Hence, several mechanical and electromagnetic constraints have been introduced in order to comply with high-speed operation, preventing demagnetization issues of ferrite magnets as well. Subsequently, an HS-BLDC characterized by an inner rotor configuration has been designed in accordance with the proposed methodology. The analytical procedure and the corresponding results have been reported and validated by means of finite element analyses, highlighting the effectiveness of the proposed configuration and design solutions.

32 citations


Journal ArticleDOI
TL;DR: Performance of various techniques in terms accuracy, memory and computational time for application specific tasks such as modeling RCS (Radar cross section), space applications, thin wires, antenna arrays are presented.
Abstract: Computational electromagnetics (CEM) is applied to model the interaction of electromagnetic fields with the objects like antenna, waveguides, aircraft and their environment using Maxwell equations. In this paper the strength and weakness of various computational electromagnetic techniques are discussed. Performance of various techniques in terms accuracy, memory and computational time for application specific tasks such as modeling RCS (Radar cross section), space applications, thin wires, antenna arrays are presented in this paper.

31 citations


Journal ArticleDOI
TL;DR: A synthesis that integrates the strengths of both FDTD and Godunov-based schemes into a robust single formulation for CED in material media is presented, with special attention paid to a second-order-accurate formulation.

30 citations


Journal ArticleDOI
TL;DR: In this paper, a full 3D frequency-domain electromagnetic modeling based on a parallel finite-difference algorithm considering the casing effect is presented and investigated on the borehole-to-surface configuration of the Hontomin CO2 storage site.
Abstract: The presence of steel-cased wells and other infrastructure causes a significant change in the electromagnetic fields that has to be taken into consideration in modeling and interpretation of field data. A realistic and accurate simulation requires the borehole casing to be incorporated into the modeling scheme, which is numerically challenging. Due to the huge conductivity contrast between the casing and surrounding media, a spatial discretization that provides accurate results at different spatial scales ranging from millimeters to hundreds of meters is required. In this paper, we present a full 3D frequency-domain electromagnetic modeling based on a parallel finite-difference algorithm considering the casing effect and investigate its applicability on the borehole-to-surface configuration of the Hontomin CO2 storage site. To guarantee a robust solution of linear systems with highly ill-conditioned matrices caused by huge conductivity contrasts and multiple spatial scales in the model, we employ direct sparse solvers. Different scenarios are simulated in order to study the influence of the source position, conductivity model, and the effect of the steel casing on the measured data. Several approximations of the real hollow casing that allow for a large reduction in the number of elements in the resulting meshes are studied. A good agreement between the modeled responses and the real field data demonstrates the feasibility of simulating casing effects in complex geological areas. The steel casing of the well greatly increases the amplitude of the surface electromagnetic fields and thus improves the signal-to-noise ratio and the sensitivity to deep targets.

29 citations


Journal ArticleDOI
TL;DR: A stable nodal integration method (SNIM) is presented to solve static and quasi-static electromagnetic problems and its effectiveness and potentialities can be well represented and clarified by numerical examples.

29 citations


Journal ArticleDOI
TL;DR: A general approach to modeling a large class of vacuum electronic devices (VEDs) by using impedance matrices to characterize the circuit structure, which can treat VEDs that have an arbitrary number of interaction gaps, severs, and input and/or output ports that may incorporate arbitrarily complex matching and/ or tuning elements and windows.
Abstract: We have developed a general approach to modeling a large class of vacuum electronic devices (VEDs) by using impedance matrices to characterize the circuit structure. Our approach can treat VEDs that have an arbitrary number of interaction gaps, severs, and input and/or output ports that may incorporate arbitrarily complex matching and/or tuning elements and windows. To find the impedance matrix for a given structure, we use the computational electromagnetics 3-D finite-element code HFSS to compute the response of the entire structure to an excitation of each individual port and gap. We define voltages and currents as certain integrals over the electric and magnetic fields, respectively, the ratios of which are elements of the generalized impedance matrix. This matrix is then imported into a beam-wave interaction code, which is used to compute VED performance (gain, output power, bandwidth, and so on). We have implemented this capability in a new 2-D code TESLA-Z, which has been verified by comparison with the large-signal code TESLA-FW and then validated by comparison with measured data from a Ka-band folded-waveguide power-booster TWT. Similar capability was also implemented in the 1-D interaction code CHRISTINE-CC.

Journal ArticleDOI
TL;DR: A new 3-D domain decomposition based hybrid finite-difference time-domain (FDTD)/finite-element time- domain (FETD) method is introduced to facilitate electromagnetic modeling by exploiting both the computational efficiency of FDTD and the meshing flexibility of FETD.
Abstract: A new 3-D domain decomposition based hybrid finite-difference time-domain (FDTD)/finite-element time-domain (FETD) method is introduced to facilitate electromagnetic modeling by exploiting both the computational efficiency of FDTD and the meshing flexibility of FETD. The proposed hybrid method allows the FETD mesh and the FDTD grid to be nonconformal based on domain decomposition technique. It implements the hybridization with a buffer zone, which functions as a transition region between FDTD and FETD. The buffer zone helps the proposed hybrid method obviate the interpolation approach for field coupling of the nonconformal mesh and hence overcome the late-time instability issue. The discontinuous Galerkin method is utilized to couple different regions, thus improving the coupling accuracy compared with that using the Dirichlet boundary condition. Moreover, the hybrid method allows further division of the FETD region into multiple subdomains when the degrees of freedom in this region are large. For temporal discretization, a global leapfrog time integration scheme is implemented to sequentially update the fields in the FDTD, buffer, and FETD regions. The numerical results are shown to demonstrate the meshing flexibility and computational efficiency of the proposed hybrid method inherited from FETD and FDTD methods.

Journal ArticleDOI
TL;DR: The electromagnetic field radiated from a standard gain horn antenna is measured using a new electromagnetic sensor using the atomic Rabi frequency and a hypothesized reduction in electromagnetic perturbation caused by the glass cell was investigated using a numerical simulation.
Abstract: A new electromagnetic sensor using the atomic Rabi frequency is presented. Gaseous cesium-133 atoms enclosed in a compact glass cell work as an electromagnetic sensor by detecting the Rabi frequency. In this paper, we measured the electromagnetic field radiated from a standard gain horn antenna using the new sensor. This result was compared with a numerical simulation based on the method of moments. Both results were in good agreement. Moreover, a hypothesized reduction in electromagnetic perturbation caused by the glass cell was investigated using a numerical simulation.

Journal ArticleDOI
TL;DR: The proposed DGTD-ACM can achieve a good numerical accuracy and reduce the computational time effectively for linear problems of EM propagation in dispersive media and is expected to provide a powerful tool for solving nonlinear EM problems in plasma physics and electronics.
Abstract: A discontinuous Galerkin time-domain (DGTD) method based on dynamically adaptive Cartesian mesh (ACM) is developed for a full-wave analysis of electromagnetic (EM) fields. The benefits of hierarchical Cartesian grids and adaptive mesh refinement are demonstrated for linear EM propagation problems. The developed DGTD-ACM achieves a desired accuracy by refining nonconformal meshes near material interfaces to reduce stair-casing errors without sacrificing the high efficiency afforded with uniform Cartesian meshes. More importantly, DGTD-ACM can dynamically refine the mesh to resolve the local variation of the fields during propagation of EM pulses. A local time-stepping scheme is adopted to alleviate the constraint on the time-step size due to the stability condition of the explicit time integration. It is shown by numerical examples that the proposed method can achieve a good numerical accuracy and reduce the computational time effectively for linear problems of EM propagation in dispersive media. With further development, the method is expected to provide a powerful tool for solving nonlinear EM problems in plasma physics and electronics.

Journal ArticleDOI
TL;DR: The main goal of this work is to determine and to correctly apply the continuity conditions on the boundary separating the two regions of an electrical machine, and to constitute a solid starting point for modeling more complex and realistic devices.
Abstract: Electrical machines employing superconductors are attractive solutions in a variety of application domains. Numerical models are powerful and necessary tools to optimize their design and predict their performance. The electromagnetic modeling of superconductors by finite-element method (FEM) is usually based on a power-law resistivity for their electrical behavior. The implementation of such constitutive law in conventional models of electrical machines is quite problematic: the magnetic vector potential directly gives the electric field and requires using a power-law depending on it. This power-law is a non-bounded function that can generate enormous uneven values in low electric field regions that can destroy the reliability of solutions. The method proposed here consists in separating the model of an electrical machine in two parts, where the magnetic field is calculated with the most appropriate formulation: the H-formulation in the part containing the superconductors and the A-formulation in the part containing conventional conductors (and possibly permanent magnets). The main goal of this work is to determine and to correctly apply the continuity conditions on the boundary separating the two regions. Depending on the location of such boundary -- in the fixed or rotating part of the machine -- the conditions that one needs to apply are different. In addition, the application of those conditions requires the use of Lagrange multipliers satisfying the field transforms of the electromagnetic quantities in the two reference systems, the fixed and the rotating one. In this article, several exemplary cases for the possible configurations are presented. In order to emphasize and capture the essential point of this modeling strategy, the discussed examples are rather simple. Nevertheless, they constitute a solid starting point for modeling more complex and realistic devices.

Journal ArticleDOI
TL;DR: In this paper, a combined field integral equation (CFIE)-based multisolver scheme is presented for electromagnetic modeling of objects with complex structures and materials, where an object is decomposed into multiple bodies based on its material property and geometry.
Abstract: A combined field integral equation (CFIE)-based multisolver scheme is presented for electromagnetic modeling of objects with complex structures and materials. In this scheme, an object is decomposed into multiple bodies based on its material property and geometry. To model bodies with complicated materials, the finite element-boundary integral (FE-BI) method is applied. To model bodies with homogeneous or conducting materials, the method of moments is employed. Specifically, three solvers are integrated in this multi-solver scheme: the FE-BI(CFIE) for inhomogeneous objects, the CFIE for dielectric objects, and the CFIE for conducting objects. A mixed testing scheme that utilizes both the Rao–Wilton–Glisson and the Buffa–Christiansen functions is adopted to obtain a good accuracy. In the iterative solution of the combined system, the multilevel fast multipole algorithm is applied to accelerate computation and reduce memory costs, and a preconditioner based on an absorbing boundary condition is employed to speed up the convergence. In the numerical examples, the individual solvers are first demonstrated to be well conditioned and highly accurate. Then, the validity of the proposed multisolver scheme is demonstrated and its capability is shown by solving scattering problems of electrically large missilelike objects.

Journal ArticleDOI
TL;DR: Numerical model study demonstrates that the quasi-analytical solution significantly reduces computation time of the seismic full-waveform inversion, and shows how it can be extended to the case of elastic wavefield.

Posted Content
TL;DR: Li et al. as discussed by the authors presented a well-conditioned decoupled potential integral equation (DPIE) formulated for electromagnetic scattering from homogeneous dielectric objects, a fully developed version of that presented in the conference communication.
Abstract: Recent work on developing novel integral equation formulations has involved using potentials as opposed to fields. This is a consequence of the additional flexibility offered by using potentials to develop well conditioned systems. Most of the work in this arena has wrestled with developing this formulation for perfectly conducting objects (Vico et al., 2014 and Liu et al., 2015), with recent effort made to addressing similar problems for dielectrics (Li et al., 2017). In this paper, we present well-conditioned decoupled potential integral equation (DPIE) formulated for electromagnetic scattering from homogeneous dielectric objects, a fully developed version of that presented in the conference communication (Li et al., 2017). The formulation is based on boundary conditions derived for decoupled boundary conditions on the scalar and vector potentials. The resulting DPIE is the second kind integral equation, and does not suffer from either low frequency or dense mesh breakdown. Analytical properties of the DPIE are studied. Results on the sphere analysis are provided to demonstrate the conditioning and spectrum of the resulting linear system.

Posted Content
TL;DR: The advantages and drawbacks of the isogeometric analysis (IGA) are reviewed in the context of electromagnetic simulations and several non-academic benchmark examples in two and three dimensions are shown which are used in optimization and uncertainty quantification workflows.
Abstract: In this communication the advantages and drawbacks of the isogeometric analysis (IGA) are reviewed in the context of electromagnetic simulations. IGA extends the set of polynomial basis functions, commonly employed by the classical Finite Element Method (FEM). While identical to FEM with Nedelec's basis functions in the lowest order case, it is based on B-spline and Non-Uniform Rational B-spline basis functions. The main benefit of this is the exact representation of the geometry in the language of computer aided design (CAD) tools. This simplifies the meshing as the computational mesh is implicitly created by the engineer using the CAD tool. The curl- and div-conforming spline function spaces are recapitulated and the available software is discussed. Finally, several non-academic benchmark examples in two and three dimensions are shown which are used in optimization and uncertainty quantification workflows.

Journal ArticleDOI
Krishnaswamy Sankaran1
TL;DR: In this article, an alternative approach to model electromagnetic problems using algebraic topology was proposed, which has a few advantages compared to the familiar differential formulation-based methods in modelling electromagnetic and multiphysics problems.
Abstract: Have you ever questioned why do we almost always use vector calculus and differential equations in electromagnetics? Are these the only tools at our disposal for studying and modelling electromagnetic problems? Well, the answer is no and this paper is about an alternative approach to model electromagnetic problems using algebraic topology. This approach has a few advantages compared to the familiar differential formulation-based methods in modelling electromagnetic and multiphysics problems. In differential formulation we need one of the several numerical methods like finite difference, finite element, method of moments and spectral methods to obtain approximate solution to the electromagnetic problem. In contrast, algebraic topology-based method leads directly to discrete formulation using global quantities. Furthermore, in the case of electromagnetics, all underlying global quantities are scalars. Hence, there is no need for vector calculus. In addition, we also avoid interpolating local vector ...

Journal ArticleDOI
TL;DR: In this article, a graphene-based photoconductive antenna (GPCA) is designed by considering its electronic and electromagnetic modeling, and an effective conductivity (non-local model) is developed for a graphene strip (GS)-based waveguide by using a semi-classical model to investigate propagation of TM-polarized surface plasmon polaritons (SPPs) by considering spatial dispersion (SD).
Abstract: In this paper, a graphene-based photoconductive antenna (GPCA) is designed by considering its electronic and electromagnetic modeling. For the electronic modeling, energy balance transport model (EBTM) is utilized, because high DC and laser powers are applied to the GPCA, and moreover, it has sub-micron dimensions. On the other hand, for the electromagnetic modeling, an effective conductivity (non-local model) is developed for a graphene strip (GS)-based waveguide by using a semi-classical model to investigate propagation of TM-polarized surface plasmon polaritons (SPPs) by considering spatial dispersion (SD). Additionally, a per unit length circuit model is proposed to validate the non-local model. Then, the GPCA’s working frequency is selected based on the electromagnetic modeling. In the EBTM, by using hot-carriers theory, saturation of photocurrent and velocity overshoot phenomenon (VOP) with regards to the applied bias are investigated. Then, a time-dependent equivalent circuit is proposed to model the GPCA’s operational principles. This circuit enables us to study screening effects in first picoseconds after excitation, which cause saturation of radiated power with respect to the illuminating laser power. Finally, via a coherent detection, radiated THz spectrum is detected through introducing a transfer function for the GPCA.

Journal ArticleDOI
TL;DR: In this paper, a diffusion equation approach was applied to modeling diffuse electromagnetic fields and evaluated its potential for use in electromagnetic compatibility applications, and two canonical examples were investigated: a loaded cavity and two cavities coupled by a large aperture.
Abstract: Determination of the distribution of electromagnetic energy inside electrically large enclosed spaces is important in many electromagnetic compatibility applications, such as certification of aircraft and equipment shielding enclosures The field inside such enclosed environments contains a dominant diffuse component due to multiple randomizing reflections from the enclosing surfaces The power balance technique has been widely applied to the analysis of such problems; however, it is unable to account for the inhomogeneities in the field that arise when the absorption in the walls and contents of the enclosure is significant In this paper, we show how a diffusion equation approach can be applied to modeling diffuse electromagnetic fields and evaluate its potential for use in electromagnetic compatibility applications Two canonical examples were investigated: a loaded cavity and two cavities coupled by a large aperture The predictions of the diffusion model were compared to measurement data and found to be in good agreement The diffusion model has a very low computational cost compared to other applicable techniques, such as full-wave simulation and ray-tracing, offering the potential for a radical increase in the efficiency of the solution high frequency electromagnetic shielding problems with complex topologies

Journal ArticleDOI
TL;DR: In this paper, the frequency domain near-field coupling effects from complicated three-dimensional transmission lines, monopole/dipole radiators, and printed circuit boards (PCBs) located in a metallic rectangular cavity with an efficient iterative fast Fourier transform-accelerated integral-equation method were analyzed.
Abstract: This paper characterizes the frequency domain near-field coupling effects from complicated three-dimensional transmission lines, monopole/dipole radiators, and printed circuit boards (PCBs) located in a metallic rectangular cavity with an efficient iterative fast Fourier transform-accelerated integral-equation method. The simulation method combines the rectangular-cavity Green's functions with the frequency-domain electric field integral equation, which is further accelerated by the extension of adaptive integral method for rectangular cavities. By using this method, the near-field coupling effects and internal field distributions are captured and compared with independent references for various structures, including transmission lines, monopole/dipole radiators, and PCBs in rectangular cavities. Numerical results show that strong couplings do appear at multiple resonant frequencies of the structures. In addition, this method can be further employed to mitigate and suppress near-field coupling effects in the optimization of electromagnetic compatibility/interference designs.

Journal ArticleDOI
TL;DR: In this article, the authors proposed contour-integral representations to evaluate the physical-optics backscattered electric and magnetic fields from a perfectly conducting object illuminated by a dipole source.
Abstract: Near-field backscattering problems are often encountered in computational electromagnetics. In this paper, contour-integral representations have been presented to evaluate the physical-optics backscattered electric and magnetic fields from a perfectly conducting object illuminated by a dipole source. The advantage of the proposed representations is that the integrands in the contour integrals along the rim of the scatterer are free from singularities for all the source/observer positions. In addition, the proposed algorithm is easily extensible to analyze the scattering from complex objects. Such a liberty is achieved by deriving the novel representations using vector-algebra theorems in global coordinates, instead of existing scalar theorems in a particular angular coordinate. Numerical examples are presented to illustrate the efficiency and accuracy of the proposed contour-integral representations.

Journal ArticleDOI
TL;DR: In this paper, a non-singular boundary integral method is used to solve directly for the field components in the frequency domain, and Fourier transform is then used to obtain the complete space-time behavior.
Abstract: The scattering of electromagnetic pulses is described using a non-singular boundary integral method to solve directly for the field components in the frequency domain, and Fourier transform is then used to obtain the complete space-time behavior. This approach is stable for wavelengths both small and large relative to characteristic length scales. Amplitudes and phases of field values can be obtained accurately on or near material boundaries. Local field enhancement effects due to multiple scattering of interest to applications in microphotonics are demonstrated.

Journal ArticleDOI
TL;DR: A review of selected computational methodologies that are based on the deterministic finite-difference time-domain algorithm and are suitable for the investigation of electromagnetic problems involving uncertainties and help the potential readers to safely select the most suitable approach for their problem under consideration.
Abstract: We provide a review of selected computational methodologies that are based on the deterministic finite-difference time-domain algorithm and are suitable for the investigation of electromagnetic problems involving uncertainties. As it will become apparent, several alternatives capable of performing uncertainty quantification in a variety of cases exist, each one exhibiting different qualities and ranges of applicability, which we intend to point out here. Given the numerous available approaches, the purpose of this paper is to clarify the main strengths and weaknesses of the described methodologies and help the potential readers to safely select the most suitable approach for their problem under consideration.

Journal ArticleDOI
TL;DR: It is expected that a transient response analysis of WPT devices will become possible in the future using this simulation architecture, and only two physical quantities needed to be exchanged between the two GPUs: self-inductance and the magnetic coupling coefficient.
Abstract: We describe a method for simulating an electromagnetic induction type wireless power transmission (WPT) device. This simulator was based on the finite-difference, time-domain method. To reduce computation time, two graphics processing units (GPUs) were used as accelerators for the electromagnetic field computation. The first GPU calculated the electromagnetic field for the non-resonance state, and the second GPU calculated the field for the resonance state. Only two physical quantities needed to be exchanged between the two GPUs: self-inductance and the magnetic coupling coefficient. Capacitors and a load resistance were virtually connected to the coils as lumped elements. The experimental and simulation results were in good agreement. It is expected that a transient response analysis of WPT devices will become possible in the future using this simulation architecture.

Proceedings ArticleDOI
01 May 2017
TL;DR: In this article, the process of plane H-polarized electromagnetic wave interaction with pre fractal system of slots in infinitely thing flat PEC screen is examined on the base of strong electromagnetic theory.
Abstract: The process of plane H-polarized electromagnetic wave interaction with pre fractal system of slots in infinitely thing flat PEC screen is examined on the base of strong electromagnetic theory. Some stage of a self similar fractal's creation is used for the system's mathematical order. The diffraction problem is treated in the classically rigorous formulation on the base of the integral equation technique. Asymptotic model of narrow slots, which has an explicit solution, is analysed in details. On the base of the asymptotic model, two main integral characteristics were considered.

Journal ArticleDOI
TL;DR: Numerical results show that a suitable chirped multilayer structure can reduce the reflection from the ground.
Abstract: The enhancement of air-ground electromagnetic matching by means of a chirped multilayer structure is investigated. The modeling and simulation of the considered structure are performed by using the method of single expression (MSE), which is a convenient and accurate tool for wavelengthscale simulations of multilayers comprising lossy, amplifying or nonlinear (Kerr-type) materials. Numerical results show that a suitable chirped multilayer structure can reduce the reflection from the ground. Different values of the number of layers and of the layer thicknesses are considered. The distributions of the electric field components and the power flow density within the modelled structures are calculated. Keywords—chirped multilayer structure, ground matching, method of single expression.