Problem Of Electromagnetic Coupling Research Articles

P‐76: The Influence of Bending FFC Transmission Line on High‐Speed Signal Channels

Generally, display devices interconnect FFC transmission lines with circuits to form a transmission line network system to achieve data communication between Tcon and Driver. Due to the limitations of the external shape and internal space structure of the display device, the FFC transmission cable presents a curved shape from 0 to 180 degrees during the wiring process. Under the action of spatial electromagnetic fields, the display device will involve the field‐circuit hybrid problem of electromagnetic coupling of the FFC transmission line's bent line and circuit conduction interference, which will cause severe electromagnetic interference(EMI), resulting in deterioration of the high‐speed channel signal at the receiving end and even inability to correctly restore and decode the signal, thus causing signal distortion, which in turn leads to display image distortion or pixel loss.

Hybrid TDPEEC/FDTD Method for Lightning Transient Analysis in Solar Panels

AbstractSolar energy is one of the clean renewable energy, which plays an important role in energy strategy. As the solar panels of photovoltaic system are installed on the outdoor roof or open area, lightning is an important threat to the safe and stable operation of photovoltaic power generation system. Because of mutual coupling among the fine‐structure solar panel, the ground and the buried wire grid, special techniques are required to develop for simulating transients in the panels. In this paper, a hybrid time domain partial element equivalent circuit/finite difference time domain (TD‐PEEC/FDTD) method was proposed to solve the electromagnetic coupling problem of the coexistence of electrically large targets and electrically small target. The FDTD method was suitable for modeling fields in inhomogeneous media, while the TD‐PEEC method was efficient in modeling elaborate wires. By using the principle of equivalence, the algorithm and the target were parallelized in different regions, which can improve the efficiency of calculation to the greatest extent on the premise of ensuring the correctness and accuracy. Compared with the traditional FDTD method, the feasibility of the hybrid method was verified. Finally, the method was applied to the lightning transient analysis of the inclined photovoltaic panel in the process of indirect lightning stroke. © 2022 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC.

A HYBRID METHOD FOR ELECTROMAGNETIC COUPLING PROBLEMS OF TRANSMISSION LINES IN CAVITY BASED ON FDTD METHOD AND TRANSMISSION LINE EQUATION

A time domain hybrid method is presented for efficiently solving the electromagnetic coupling problems of transmission lines in cavity. The proposed method is based on the finite-difference time-domain (FDTD) method and transmission line (TL) equations (FDTD-TL), which can achieve a strong synergism on the computations of field and circuit. The FDTD method with an auto mesh generation technique is employed to obtain the electric fields of transmission lines excited by an incident wave from the outside of the cavity. The electric fields are introduced into the TL equations as additional voltage sources at each time step of FDTD method. The current and voltage responses of terminal loads can be obtained by the TL equations. Two examples are presented to demonstrate the correctness of this method. The high efficiency of this hybrid method is verified by comparing the computation time with the traditional method.

Finite Element Analysis on Eddy Current Field of a Large Inner Feedback Motor

To solve the problem of electromagnetic coupling of the main winding and the inner feedback winding, this paper built a 2D finite model of the inner feedback motor and simulated the magnetic field on rated load. Distribution of flux density and flux line is obtained, which provides the reference for optimization, controlling and fault analysis for these motors.

A simplified approach to modeling the interaction between grounding grid and lightning stroke

In this work, a new approach for the modeling of the interaction between grounding grid and lightning stroke is described. We treat the case of direct and indirect effects of lightning strike. In the case of direct impact, we inject in point of grounding system a current with bi-exponential wave shape and we calculate the distribution of potentials and currents on the grid and the electromagnetic field it will emit. For the second case, we treat a problem of electromagnetic coupling, which is to calculate the induced currents that developed on the grounding grid when this later is illuminated by a lightning channel located in its vicinity. The presented model is validated by comparing the obtained results to the results arising from the full wave (antenna) model available in literature and to the results obtained by using NEC4 software. The principal advantage of the presented approach is the simplicity of the implementation providing a direct determination of the both current and potential distribution along the grounding grid and the related electromagnetic field in an arbitrary point in the air and/or soil, as well.

Dynamic behaviors of conductive circular plate in time-varying magnetic fields

In this study, we proposed an analytical solution for eddy currents as well as electromagnetic forces of a conductive circular plate in a time varying magnetic field. Specifically, an analytical series solution for eddy currents in a circular plate subjected to an axisymmetric time varying magnetic field has been proposed based on the T-method that has been widely used in the eddy current analysis of conductive and superconductive structures. Accordingly, the dynamic response, the dynamic instability and the magnetic damping of a circular plate in a transverse transient magnetic field as well as a stationary in-plane magnetic field have also been obtained. The analytical series solution proposed in this work as well as the subsequent numerical analysis not only confirmed the emergence of dynamic instability of a circular plate in a strong transverse magnetic field, but also demonstrated the existence of magneto-damping of a circular conductive plate in an in-plane magnetic field. The method developed in this paper provides a potential new possible way by which the analysis of the electromagnetic coupling problems of conductive structures can be simplified.

Transient Response of a Multiconductor Transmission Line With Nonlinear Terminations Excited by an Electric Dipole

A method for transient analysis of multiconductor transmission lines with nonlinear terminations excited by an electric dipole is presented in this paper. The solution to the initial boundary value problem represented by transmission-line equations and initial and boundary conditions is proved to be unique, under the assumption that the terminations are locally passive nonlinear resistors. The current Baum-Liu-Tesche equation in the complex frequency domain is divided into two parts representing responses excited separately by terminal voltages of the loads and distributed voltage sources produced by the electric dipole. Furthermore, the equivalent resistance of each exciting voltage source is derived to be zero. Time-domain equations to resolve the problem are established. In contrast with calculation results by other methods, it is shown that the method proposed in the paper can be used to efficiently calculate the electromagnetic coupling problem of an external electromagnetic field and multiconductor transmission line with nonlinear terminations.

Electromagneto-thermo-mechanical behaviors of conductive circular plate subject to time-dependent magnetic fields

This paper presents an analysis on electromagneto-thermo-mechanical behaviors of conductive plates, an analytical solution is given for a conductive circular plate in a time-dependent magnetic field by using a T-method of the eddy current which is widely used in the eddy current analysis of conductive and superconductive structures. The solution is expressed in an analytical series form and it is suitable for a circular plate under any arbitrary axisymmetric magnetic fields changing in time. Some interesting results including the eddy current, the increment of temperature, and the electromagneto-thermal stresses are investigated, respectively, in this paper. Some characteristics such as the distribution of temperatures, the in-plane electromagnetic stresses and the dynamic response of the conductive plate are first studied and displayed. This study not only reveals some characteristics on the eddy current, the temperature of the plate, the in-plane electromagnetic thermal stresses and the dynamic responses of the conductive plate which is in a time-dependent magnetic field, but presents a new possible way to simplify the analysis of the electromagnetic coupling problem for conductive structures.

A Study on the Coupling of a Flanged Parallel-Plate Waveguide to a Slit In a Nearby Conducting Screen for Near-Field Scanning Microscopy

The problem of electromagnetic coupling between a slit fed by a flanged parallel-plate waveguide(PPW) and a slit in an infinite nearby conducting screen parallel to the flanged ground conductor is studied as a simplified problem for a near-field scanning microscopy(NSM). The method of moments isused to solve the coupled integral equations for the electric field distributions over the slits. The performance of the proposed apparatus as an NSM is tested by examining the effects of some geometrical parameters on the equivalent slit admittance and coupled powers through the slits.

도체 스크린의 좁은 슬릿을 통한 전자파 최대 투과 현상

본 연구에서는 무한 도체판의 좁은 슬릿에 TM 편파된 평면파가 입사되는 경우의 전자기적 결합 문제를 고려 하였다. 등가 회로를 이용하여 공진된 슬릿을 통한 최대 전력 투과 메커니즘을 설명하는데 연구의 주안점을 두었다. 슬릿이 공진되었을 때 좁은 슬릿을 통해 투과된 전력은 슬릿 폭에 무관하게 유효 슬릿 폭 1/pi 파장에 도달되는 전력과 동일함을 보였다. 제안된 구조와 두꺼운 도체 스크린에서의 좁은 슬릿을 통한 최대 전력 투과 현상들의 유사성을 등가 회로의 관점에서 기술하였다. 또한, 공진이 일어났을 때 슬릿에 의한 산란 전력과 슬릿을 통한 투과 전력이 동일함을 확인하였다. In this study, the electromagnetic coupling problem through narrow slit in an infinite conducting screen is considered for the case that the TM polarized plane wave is incident upon the slit. This study aims at explaining the mechanism of the maximum power transmission via the resonated slit using the equivalent circuit. It is shown that the transmitted power through the slit for the case of resonance corresponds to the power normally incident upon the conducting plane of the effective width 1/pi wavelengths, irrespective of the slit width. Some similarities between the maximum power transmissions observed in both the proposed structure and narrow slit in thick conducting screen are described from the viewpoint of equivalent circuit. In addition, it is found that, when the slit is resonated, the transmitted power equal to the scattered power.

Electromagnetic coupling mechanism to a conducting strip through a narrow slit in a parallel-plate waveguide

The problem of electromagnetic coupling to a conducting strip through a narrow slit in a parallel-plate waveguide (PPW) is reconsidered with an emphasis on the radiative coupling mechanism. Two different types of coupling are discussed: cavity and parasitic. The maximum coupled power in both cases is observed to be almost the maximum available power from the slit (half of the incident power in the PPW), even though the two types of coupling are quite different from each other in their equivalent circuit representation or coupling mechanism. The similarity between the problem of cavity-type coupling and the previously reported transmission resonance problem through a narrow slit in thick screens is also described in connection with the aperture-body resonance phenomenon.

Electromagnetic Transmission through Apertures of Arbitrary Shape in a Conducting Screen

In this paper, the general problem of electromagnetic coupling between two dissimilar regions, both open at infinity, via an aperture of arbitrary shape is considered. The aperture is assumed to be located in a conducting screen of infinitesimal thickness. The analysis is based on the “generalised network formulation” for aperture problems. Field equivalence principle is first used to divide the problem into two parts. Next, boundary conditions are invoked to obtain a magnetic field integral equation (MFIE) which is then solved using the method of moments (MOM). Triangular patches, with appropriately defined basis functions, are used to model the arbitrarily shaped aperture. This leads to a matrix equation whose solution requires the evaluation of integrals with bounded and unbounded kernels over a triangular domain. Representative results are given for rectangular, circular, elliptic, diamond-shaped, cross-shaped and H-shaped apertures.

Synthesis of an array antenna for hyperthermia applications

In the present work the synthesis of an array antenna for hyperthermia treatment is developed. The selected antenna is an array antenna surrounded by a semicircular reflector which has shown to ease the penetration and focalization in malignant biological tissues. A bolus is introduced as a protection in order to avoid an increasing heat hazard of superficial healthy tissues. The electric field within the biological medium will be modeled by means of the well known method of moments. The electromagnetic coupling problem is expressed in a closed form, enabling both a synthesis and an optimization procedure to be performed. Numerical results are included, illustrating the capabilities of the array antenna.

Design of a microwave array hyperthermia applicator with a semicircular reflector.

The design of a hyperthermia applicator for heating biological tissues is presented in which the applicator consists of an array antenna surrounded by a perfect electrically conducting reflector. The heat hazard to superficial tissues is reduced by the introduction of a dielectric protecting layer over them. A method of moments formulation is applied to approximate the electric field within the biological medium and a closed form expression is presented for the electromagnetic coupling problem, which enables an optimisation procedure to be performed. The applicator enhances both penetration and focusing: deep tumours, close to the bone region, are heated and the percentage of biologically healthy tissue exposed to a specific absorption rate (SAR) hazard level diminishes by 53.8%.

Electromagnetic radiation and scattering at the American University of Beirut

This paper presents the work carried out at the American University of Beirut on electromagnetic radiation and scattering, using the characteristic-modes theory. Several problems of various two-dimensional and three-dimensional geometrics have been considered: slots in a plane, slots in a conducting cylinder, a parallel plate-fed slot antenna, an aperture-fed waveguide, a rectangular aperture in a perfectly conducting plane, a cavity-backed aperture. The characteristic modes for each geometry were first computed, and the convergence of the solution was tested for all these problems. A combined characteristic-modes formulation, for the problem of electromagnetic coupling to conducting objects behind arbitrary apertures in a conducting plane, has been developed and used to solve many of these problems.

Electromagnetic coupling to conducting objects behind apertures in a conducting body

A procedure for computing characteristic modes for the problem of electromagnetic coupling to arbitrary shape conducting objects behind arbitrary shape apertures in a conducting body is developed starting from the operator formulation of the currents. The mode currents are obtained from the admittance and impedance operators. This formulation is general and characterized by its simplicity and efficiency. This method is applied to a finite thin wire backed by a rectangular aperture in a conducting plane in an unbounded medium. The integral equations in terms of the magnetic and electric current distributions are derived for the magnetic and electric fields. The moment method is used to obtain matrix equations approximating the integral equations. The expansion functions are chosen to satisfy the continuity equations and to vanish at the wire endpoints. Finally, modal solutions are computed to illustrate the convergence of the solution as the number of modes increases.

Electromagnetic coupling between two half-space regions separated by multiple slot-perforated parallel conducting screens

Considers the problem of electromagnetic coupling between two half-space regions separated by multiple slot-perforated parallel conducting screens. The fields are considered to be excited by either a transverse electric (TE) or a transverse magnetic (TM) plane wave. A characteristic mode solution is used for the computation of the fields in each half-space. Special attention is given to the power transmitted from one half-space to the other through the slots and to its functional dependence on various parameters. Numerical examples are presented for illustration and comparison.< <ETX xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">&gt;</ETX>

Transient coupling analysis using the singularity expansion method

The problem of electromagnetic coupling between objects has been extensively studied within the context of continuous-wave (CW) signals. The problem of coupling between objects for transient excitation has not received as much attention. This paper addresses the problem of transient coupling using the singularity expansion method (SEM). Specifically, the proper physical interpretation of the SEM modes of a system of objects is discussed within the context of observed transient surface currents and scattered fields. It is seen that the SEM modes of the system of objects are global quantities and hence have no clear physical interpretation prior to times when global modes can be established. It is also apparent that the early-time response of the system can be expressed using the SEM modes of the individual objects for some time periods. These observations are important for the effective use of target identification schemes based on natural resonance phenomena in multiple target situations as well as the proper use of SEM in EMC coupling analyses. >

Characteristic mode analysis off electromagnetic coupling through multiple slots in a conducting plane

The problem of electromagnetic coupling through slots in a conducting plane is studied using characteristic-mode theory; i.e. the problem is formulated as an operator equation whose solution determines the characteristic modes of the problem. The cases treated are those when the plane is excited by either a transverse electric (TE) or a transverse magnetic (TM) plane waves with different angles of incidence. It is assumed that the media to the right and to the left of the plane exhibit different electromagnetic properties. Where comparison is possible, there is a good agreement with classical results. The computer program is described briefly, and representative examples are given.

Electromagnetic coupling between two half-space regions separated by two slot-perforated parallel conducting screens

The problem of electromagnetic coupling between two half-space regions separated by two slot-perforated parallel conducting planes is investigated. A general moment solution for the problem is obtained. This moment solution is then specialized to the case of narrow slots and to a TE (transverse electric to the slot axis) excitation. Attention is given to the power transmitted from one half-space to the other through the slots and to its functional dependence on various problem parameters involved. >