Electromagnetic Field Simulation Research Articles

Electromagnetic Compatibility Analysis and Optimization Design of Switching Power Supply Printed Circuit Board

Printed Circuit Board (PCB) is not only an important electrical module of information equipment, but also an important source of electromagnetic radiation. Only when PCB works normally and is compatible with other electrical equipment, the whole information equipment can work normally. Because of the complexity of PCB structure and the difficulty of modeling, the EMC (Electromagnetic Compatibility) analysis of PCB is very difficult. For this reason, Taking the widely used full bridge current double rectifier converter as an example, aiming at the electromagnetic compatibility problems caused by the PCB design of the switching power supply, this paper proposes a simulation method based on the electromagnetic field by establishing the near-field radiation model of the PCB, analyzes the areas with high radiation intensity in the PCB layout, by optimizing the layout and wiring of the PCB, the electromagnetic compatibility performance of the switching power supply is improved. The simulation results show that the near-field radiation characteristics of PCB can be predicted by introducing the electromagnetic field simulation method in the design stage, according to the characteristics of the magnetic field, the optimal design is realized, so that the EMC of the switching power supply reaches the standard, and finally the working performance of the switching power supply is improved.

Modeling and Simulation of Electromagnetic Field of Electromagnetic Coil Launcher

Electromagnetic coil launcher is a kind of special linear motor. In order to study the trigger principles of multi‐stage electromagnetic coil launcher, based on the electromagnetic field theory, the paper deduced the field‐circuit coupling magnetic field control equations of multi‐stage synchronous inductive coil with the consideration of inter‐stage coupling, and analyzed the distribution law of magnetic lines of force, air‐gap magnetic field and current density for multi‐stage electromagnetic coil launcher. The following conclusions were reached: the largest part of magnetic flux was at the intermediate stages of multi‐stage electromagnetic coil launcher; each stage of drive coil compensates for the magnetic field of the upper coil, thus making a stable air‐gap magnetic field; the induced current density was mainly distributed in the tail and surface of the armature; according to anti‐electromagnetic shock design principle of multi‐stage electromagnetic coil launcher (namely, the requirement for small fluctuation of electromagnetic force), the basic principle of multistage trigger was summarized, that is the principle of keeping air‐gap magnetic field and induced current constant. Thus, the design foundation was laid for the operation of multistage electromagnetic coil launcher. © 2021 Institute of Electrical Engineers of Japan. Published by Wiley Periodicals LLC.

Optoplasmonic film for SERS

Combining plasmonic and photonic elements, optoplasmonic hybrid structure exhibits excellent optical properties beyond conventional plasmonic or photonic structures. In this work, the optoplasmonic film consists of SiO2 microsphere and Au film without any nanostructures is investigated. With the help of a microsphere, the intensity of surface enhanced Raman spectroscopy (SERS) on Au film is highly enhanced (~1000 times) compared to bare Au film. The simulated electromagnetic field points out the enhancement caused by the optical lens effect of SiO2 microsphere that high light intensity is generated under the microsphere to excite surface plasmon on Au film. Furthermore, our data demonstrates the microsphere lens enhancement is greatly influenced by the size of the SiO2 microsphere and wavelength of incident light. This interesting film with a simple configuration could overcome the challenges in the fabrication and store process induced by nanostructures, which play an important role in SERS application. Our work not only enlarges the knowledge of the optoplasmonic hybrid structure, but also exhibits excellent application prospective in light harvest field e.g. enhanced spectrum, photocatalysis, optothermal effect, and hot electron generation, etc.

Self-sustainable and recyclable ternary Au@Cu2O\u2013Ag nanocomposites: application in ultrasensitive SERS detection and highly efficient photocatalysis of organic dyes under visible light

Ternary noble metal–semiconductor nanocomposites (NCs) with core–shell–satellite nanostructures have received widespread attention due to their outstanding performance in detecting pollutants through surface-enhanced Raman scattering (SERS) and photodegradation of organic pollutants. In this work, ternary Au@Cu2O–Ag NCs were designed and prepared by a galvanic replacement method. The effect of different amounts of Ag nanocrystals adsorbed on the surfaces of Au@Cu2O on the SERS activity was investigated based on the SERS detection of 4-mercaptobenzoic acid (4-MBA) reporter molecules. Based on electromagnetic field simulations and photoluminescence (PL) results, a possible SERS enhancement mechanism was proposed and discussed. Moreover, Au@Cu2O–Ag NCs served as SERS substrates, and highly sensitive SERS detection of malachite green (MG) with a detection limit as low as 10−9 M was achieved. In addition, Au@Cu2O–Ag NCs were recycled due to their superior self-cleaning ability and could catalyze the degradation of MG driven by visible light. This work demonstrates a wide range of possibilities for the integration of recyclable SERS detection and photodegradation of organic dyes and promotes the development of green testing techniques.

Numerical Simulation of Flow, Heat, Solidification, Solute Transfer and Electromagnetic Field for Vertical Mold and Curved Mold of Billet

Numerical Simulation of Flow, Heat, Solidification, Solute Transfer and Electromagnetic Field for Vertical Mold and Curved Mold of Billet

Electromagnetic wave absorption of periodic cylindrical structured gypsum composites incorporate with different carbonaceous materials

To improve the impedance matching condition and broaden the effective absorbing bandwidth, a series of cylindrical periodic structured gypsum composites with different kinds of carbonaceous materials as absorbents were fabricated by two-step molding process. The influences of the mass fraction of helical carbon fiber (HCF), carbon nanotube (CNT), and graphene (GE) on the morphology, permittivity, resistivity, and electromagnetic (EM) wave absorbing properties of the proposed gypsum composites were investigated. The experimental results show that the composite with 2 wt% HCF exhibits optimum EM wave absorption performance, its reflection loss is lower than − 10 dB in 2–18 GHz and bandwidth thickness ratio coefficient reaches 0.8 GHz/mm. The EM wave absorption mechanisms were further explained by the simulation of EM field and power loss distribution. The dielectric loss of carbonaceous absorbents, the destructive interference, and the EM wave diffraction and multiple refractions caused by the periodic cylindrical arrays are the main EM wave attenuation mechanisms of the fabricated composites. This study could provide guidance for the design of broadband EM wave absorbing materials.

Development of Magnetostriction-Based Non-Contacting Ultrasonic Guided Wave Testing For Ferromagnetic Pipes Using HTS-SQUID Gradiometer

In this work, a magnetostriction-based non-contacting ultrasonic guided wave testing (UGWT) technique was developed and demonstrated. Magnetization method to transceive T (0, 1) mode ultrasonic guided wave (UGW) on pure nickel thin pipe was studied with both electromagnetic field simulator and experiments. The latter utilized HTS-SQUID gradiometer as a part of receiver of the UGW. In the both studies, a pair of electromagnets sandwiching the Ni pipe was used to magnetize the pipe, while rotating the pipe between the electromagnets. The simulation results indicate the magnetization method can give roughly uniform remnant magnetic field of about 240 mT in the circumference of the Ni pipe with supplying 15 A DC current to the electromagnets. In the experiments, we successfully transceived T (0, 1) mode UGWs on the Ni pipe using the magnetization method and the HTS-SQUID gradiometer. All-round UGWT around the pipe was conducted with lift-off distance of about 10 mm. The experimental result indicated that the magnetization distribution in the circumference of the pipe was roughly uniform as well as the simulation result. Improvement of the uniformity of the magnetization was realized with stepwise magnetization and resulted in better uniformity in the magnetic signal peak distribution. The reason of the better uniformities by the new magnetization method is discussed.

Multi physical field coupling simulation analysis of power transformer vibration and noise

The generation, propagation and distribution of power transformer vibration and noise are studied by modeling and simulation. Based on the theoretical analysis of the mechanism of power transformer vibration and noise, the correlation between the characteristics of power transformer vibration noise and the influencing factors is determined. The solid model of single-phase power transformer is established by using multi physical field finite element analysis software. The multi physical field coupling simulation of electromagnetic field, structural force field and pressure acoustic field is carried out. The spatial distribution and frequency characteristics of vibration and noise signal of single-phase power transformer in each solution domain are displayed. It provides theoretical and technical support for smart grid equipment detection and environmental noise comprehensive control.

Design of millimeter wave radar amplification module

In this paper, the millimeter wave radar amplification device is designed using the MWG303 power amplifier chip of Milliway Electronic Technology Co., Ltd. The whole device comprises an input waveguide microstrip transition structure based on Rogers 5880 and an output waveguide microstrip transition structure based on quartz. And waveguide structures such as waveguide turn and waveguide lift, in this design, the waveguide microstrip transition circuit is designed and simulated in the 3D electromagnetic field simulation software HFSS of Ansoft Company, and then the parts are combined, and the micro-assembly test is carried out after CAD processing. The results show that the gain can reaches more than 10dB. The design has the advantages of high gain, good flatness, practical structure and so on.

Multi-Channel RF Supervision Module for Thermal Magnetic Resonance Based Cancer Therapy.

Simple SummaryGlioblastoma multiforme (GBM) is the most lethal brain tumor. Combining hyperthermia with chemotherapy and/or radiotherapy improves survival of GBM patients. For radio frequency (RF)-induced hyperthermia, the RF signals’ power and phase need to be supervised to achieve a precise formation of the power deposition focal point, accurate thermal dose control, and safety management. Patient position during treatment also needs to be monitored to ensure the efficiency of the treatment and to avoid adverse effects in healthy tissue. This work demonstrates the development, implementation, evaluation, validation, and application of a multi-channel RF supervision module that meets the technical requirements of hyperthermia and provides a cost-effective solution for broad-band RF signal supervision and patient monitoring. It is a key component for a hyperthermia hardware system and facilitates future thermal magnetic resonance applications that integrate RF-induced heating, in vivo temperature mapping, and anatomic and functional imaging in a single RF applicator.Glioblastoma multiforme (GBM) is the most lethal and common brain tumor. Combining hyperthermia with chemotherapy and/or radiotherapy improves the survival of GBM patients. Thermal magnetic resonance (ThermalMR) is a hyperthermia variant that exploits radio frequency (RF)-induced heating to examine the role of temperature in biological systems and disease. The RF signals’ power and phase need to be supervised to manage the formation of the energy focal point, accurate thermal dose control, and safety. Patient position during treatment also needs to be monitored to ensure the efficacy of the treatment and avoid damages to healthy tissue. This work reports on a multi-channel RF signal supervision module that is capable of monitoring and regulating RF signals and detecting patient motion. System characterization was performed for a broad range of frequencies. Monte-Carlo simulations were performed to examine the impact of power and phase errors on hyperthermia performance. The supervision module’s utility was demonstrated in characterizing RF power amplifiers and being a key part of a feedback control loop regulating RF signals in heating experiments. Electromagnetic field simulations were conducted to calculate the impact of patient displacement during treatment. The supervision module was experimentally tested for detecting patient motion to a submillimeter level. To conclude, this work presents a cost-effective RF supervision module that is a key component for a hyperthermia hardware system and forms a technological basis for future ThermalMR applications.

Design of coaxial and waveguide couplers for helix TWT

Abstract In this paper, two types of coaxial coupler and waveguide coupler for different frequency helix traveling wave tubes (TWTs) are designed, fabricated and cold tested. The coaxial coupler includes of window ceramic and RF transformer section. At present multi-section impedance transformer design approach is used for wideband helix TWTs. In any helix TWT, impedance of the source is transformed to the characteristic impedance of helix. This is done by the quarter-wavelength (λ/4) impedance transformation approach. The simulated results of different types of couplers are carried out by HFSS and CST microwave studio software and compare with experimental results. Three-dimensional electromagnetic field simulators allowing the any geometry with port excitations it is possible to model the complex coaxial and waveguide type couplers with helix SWS assembly and predict its desired return loss performances.

Improving the threshold of multipactor using a graded permittivity dielectric window

To suppress the onset of multipactor breakdown on a dielectric surface, a graded permittivity dielectric material is introduced to replace a classical single uniform dielectric material. The electromagnetic field simulation results show that the peak value of the microwave electric field will increase when the center of the microwave window is constructed from a material with a high relative permittivity. However, when the edge of the microwave window is made of such a material, the peak of the microwave electric field will decrease. In addition, the process of multipactor breakdown is investigated using the 2D particle-in-cell method. The results show that the maximum density of electrons that occurs when the edge of the microwave window is constructed from a high-relative-permittivity material is only 66.05% of that which occurs with a uniform dielectric material. As a result, the threshold of multipactor breakdown can be improved. The results reported in this paper can be used to guide the design of microwave windows.

Simulation of electromagnetic and thermal fields in the process of induction heating on small specimens with the presence of welded joint of high-strength railway rails

The Paton Welding Journal, 2021, №01. International Scientific-Technical and Production Journal «The Paton Welding Journal» «The Paton Welding Journal» has been published monthly since 2000 in English, ISSN 0957-798X. «The Paton Welding Journal» is a cover-to-cover English translation of the «Avtomaticheskaya Svarka» (Automatic Welding) journal. The «Avtomaticheskaya Svarka» journal has been published monthly since 1948 in Russian, ISSN 005-111X.

Convolutional Neural Network 기반 EBG 구조 설계를 통한 고속 PCB 노이즈 저감

With rapid advances in technology, the operating frequencies of digital systems have increased to several GHz bands. This has led to an increase in simultaneous switching noise(SSN). To reduce SSN, electromagnetic bandgap(EBG) structures have been intensively studied. One of the critical steps in the design of an EBG structure is to predict the stopband that reduces SSN. Existing methods include using a 3D electromagnetic field simulation program or equations based on the Floquet theory. However, these have limitations. In this study, we verified a new method for predicting the stopband using a convolutional neural network(CNN). Specifically, a CNN architectural model was used to compare structures that perform well in predicting the stopband. It was also used to confirm that the DenseNet showed high performance.

An Introductory Note on Finite Element Problems Based on the Eddy Current Testing Approach

The paper addresses the first eddy current benchmark problem proposed by the World Federation of Nondestructive Evaluation Centers (WFNDEC). The problem simulates the eddy current response to the presence of an axisymmetric circumferential defect in an Inconel-600 tube. All simulations employ the axisymmetric code of the electromagnetic field simulator Finite Element Method Magnetics. For three different frequencies of excitation, it is explained how the displacement of the detecting coil inside the tube leads to a variation in the impedance of the eddy current coil. Variations of the resistive and inductive components of the impedance with distance from the defect region are used to build the impedance trajectory for each frequency of analysis.

Directional Antenna With Lightweight Metamaterial Reflector for UAV-Based Networks

The wireless relay network utilizing multiple Unmanned Aerial Vehicles (UAVs) has now been widely studied. Since the radio propagation in the UAV network is close to free space environment, co-channel interference to other UAVs and the ground station (GS) becomes a serious problem. Designing a directional and multiband antenna is quite effective against this issue; multiple metamaterial reflectors are our key solution. Meanwhile, the flight time of the UAV imposes a limitation on the payload weight including communication equipment. This paper proposes a directional antenna employing a lightweight metamaterial reflector to reduce the antenna weight. It is realized by the woodpile structure which consists of layers of dielectric rods with a stacking sequence. Making the hole in the center of each dielectric rod can reduce the woodpile reflector's weight with maintaining the antenna radiation performance. The electromagnetic field simulation clarified the reflection characteristics by making the hole. Both simulative and experimental evaluations clarified that the proposed antenna has almost the same radiation characteristics as the conventional one while reducing its weight by 25%, which saves the power consumption by 12.5%.

Effect of Unit Cell Shape on Switchable Infrared Metamaterial VO2 Absorbers/Emitters.

Metamaterial absorber/emitter is an important aspect of infrared radiation manipulation. In this paper, we proposed four simple switchable infrared metamaterial absorbers/emitters with Ag/VO2 disks on the Ag plane employing triangle, square, hexagon, and circle unit cells. The spectral absorption peaks whose intensities are above 0.99 occur at ~4 μm after structure optimization when VO2 is in insulating state and disappear when VO2 becomes metallic state. The simulated electromagnetic field reveals that the spectral absorption peaks are attributed to the excitation of magnetic polariton within the insulating VO2 spacer layer, whose values exceed 1.59 orders of magnitude higher than the incident magnetic field. Longer resonant wavelength would be excited in square arrays because its configuration is a better carrier of charges at the same spans. For absorption stability, the absorbers/emitters with square and circular structures do not have any change with the polarization angles changing from 0° to 90°, due to the high rotational symmetric structure. And four absorbers/emitters reveal similar shifts and attenuations under different incident angles. We believed that the switchable absorber/emitter demonstrates promising applications in the sensing technology and adaptive infrared system.

Impact of the dielectric duty factor on magnetic resonance in Ag-SiO2-Ag magnetic absorber

Magnetic absorber in optical frequency can be fulfilled through metamaterials designing. Therein, magnetic resonance in metal-dielectric-metal metasurfaces can be manipulated conveniently, and studying the parameters impacts is the primary for applications. In this work, through changing the grating width and the thickness of silica, the magnetic resonance modes have been studied, the conditions of the phase change zone from magnetic resonance (MR) to Fabry-Perot (FP) are given out in Ag−SiO2−Ag grating magnetic metasurfaces. The results indicate that the MR mode in metal-dielectric-metal configuration is mainly decided on the dielectric duty factor other than the sole behaviors of the thickness of dielectric and size of nanostructures. The physical mechanism is elucidated through simulated electromagnetic field distributions using finite difference time domain (FDTD) solution, and numerical analysis of effective refraction index of Ag−SiO2−Ag magnetic metasurfaces. This study may prompt development of metamaterials in basic research in condensed physics and in optical devices applications.

Model of electromagnetic field effect on biological tissues.

The design of modern devices for extracorporeal magnetotherapy should be preceded by physical and mathematical modeling of all stages of the technology of the effect of magnetic fields on various types of body tissues, taking into account their dielectric properties. This is necessary to create an electromagnetic field with the necessary biotropic parameters. In this work, a mathematical model of the effect of electromagnetic field on biological tissues, such as muscles, skin and adipose tissue, is constructed. The mathematical model takes into account various parameters of biological tissue, such as electrical conductivity and relative dielectric constant. Based on the model, the parameters of the response in biological tissues (the amplitude of the response in the tissue and the maximum value of the current in the tissue) were calculated in the innovative Sim4Life 5.2 platform. To test the mathematical model, a laboratory model was used to measure the electrical characteristics of biological tissue. During the research, experiments were carried out with three biological samples: adipose tissue, muscle tissue and skin. The dependences of the response amplitude in biological samples on the output signal power are plotted. The results obtained characterize the use of the proposed operation algorithm in a complex based on the Sim4Life 5.2 platform and simulation of electromagnetic field with a biological object that is optimal for the creation and examination of technologies and devices for magnetotherapy and inductors of extracorporeal effects of magnetic field. This work will make it possible to familiarize a wider range of different experts with the capabilities of the platform not only for modeling new medical devices, but also for the examination of available and those already applied in healthcare.

Simultaneous enhancement of luminescence and stability of lead halide perovskites by a diatomite microcavity for light-emitting diodes

Lead halide perovskite quantum dots (Pe QDs) are revolutionizing the photoelectric field and hold considerable potential for future applications. However, the simultaneous promotion of both high luminescence performance and excellent stability is still a major challenge for its practical application. Herein, we presented a diatomite mineral with naturally optical microcavity is used to construct polyacrylic acid-grafted diatomite (DE-g-PAA) mediate reactors for in-situ crafting CsPbX3 QDs (X = Cl, Br and I). The as-prepared CPB (CsPbBr3) -DE-g-PAA composite emitters not only preserve a higher photoluminescence quantum yield about 76.4% ± 0.7% compared to 33.1% ± 0.5% for CPB but also present outstanding thermal stability and water-resistance property. This luminescence improvement further be confirmed as the electromagnetic field enhancement from resonance effect of cavities with uniform size in the diatomite via electromagnetic field simulations. This study provides new insights for achieving stable and highly efficient CsPbX3 QDs-based multifunctional materials using natural clay minerals with quasi-photonic crystal structure.