Electromagnetic Simulation Software Research Articles

Computational analysis of electromagnetic field exposure in passengers near high- current contact wire environments.

The electromagnetic environment of a railway station is composed of electrical, magnetic, and electromagnetic fields, which are generated by various sources such as traction current, voltage, pantograph-catenary arc, locomotive braking, wheel-rail rolling arc, and communication systems. However, there is public growing concern among the public about the potential negative human health effects of this electromagnetic environment. To analyze the distribution of electromagnetic fields in human tissues, electromagnetic simulation software is used to create a model that includes six track contact wires and four waiting passengers on three platforms. This model is used to analyze the magnetic field environment created by high currents in the contact wires of a multi-track high-speed railway station. By varying the loads on different contact wires, the distribution of electric field and magnetic flux density within human tissues of waiting passengers on different platforms is studied using this model. When the track is unoccupied, the calculation results show that the maximum values of the electric field and magnetic flux density of the passenger's human body tissue at the blind way on the platform and 1m of the blind way are 17.6mVm-1 and 52.7 μT, respectively. These values increase by 9.28mVm-1 and 16.4 μT compared to when the track is occupied. When more contact wires are loaded with currents, the electric field mode and magnetic flux density mode of human tissues increase at the same position on the platform. Specifically, when the contact wires of six tracks are loaded with current at the same time, the maximum values of the electric field mode and magnetic flux density mode of the waiting passengers' human tissues at the blind way on different platforms are 29.6mVm-1 and 88.1 μT, respectively. These maximum values are lower than the public electromagnetic exposure limits that are designated by the International Commission on Non-Ionizing Radiation Protection guidelines. The research results demonstrate that the magnetic field environment generated by the current in the contact wires of a railway station with six tracks does not pose a health risk to human tissues of passengers waiting at the blind way and 1m of the blind way on the platform. These findings can provide valuable data reference for the formulation of relevant standards for the design of electrified rail transit, as well as the suppression of electromagnetic interference and protection of human bioelectromagnetism.

Numerical model of the QiTai radio Telescope PAF receiver signal and simulation of interference mitigation

Xinjiang Qitai is constructing a 110-m fully steerable radio telescope (QiTai radio Telescope [QTT]) equipped with a phased array feeds (PAF) receiver, which will install the focal plane operating from 0.7 to 1.8 GHz. In this article, we introduce a PAF receiver model for beamforming, and the numerical model of the internal and external noise for this PAF receiver is provided using electromagnetic field simulation software. The linear constraint minimum variance (LCMV) algorithm is used to simulate the interference mitigation. The interference mitigation rate is from 0.581 to 0.921, and the signal restoration rate is from 0.998 to 1.512 within the error range of an interference arrival angle of 10°. This conclusion can be used in the signal correction of the PAF receiver for interference mitigation.

Optimization design of TEM cell based on multi-stage curved edge transition structure and magnetic loss method

This article describes how to raise the TEM cells' operating bandwidth and lower their VSWR. A multi-stage curved-edge transition structure for minimizing VSWR and a magnetic loss mechanism for extending the operating bandwidth are proposed by evaluating the workings and constraints of TEM cells. A hybrid simulation strategy based on the particle swarm algorithm and 3D electromagnetic simulation (EM) software is suggested in order to identify the optimal quickly. In the 3D EM simulation software, the TEM cell's 3D model is created, the VSWR and return loss were solved for. It is possible to raise the operational bandwidth from 0–2 GHz to 0–5 GHz. At 0-3 GHz, measurement and simulation results are practically equal. At 3-4.5 GHz, measurement results differ somewhat from simulation results. At 4.5-5 GHz, measurement results greatly diverge from simulation results, and the parameters no longer fulfill standard criteria.

Single pulse lightning and multiple lightning intrusion overvoltage in 500 kV GIS substation

Abstract Lightning intrusion wave is a key factor threatening the safe operation of substations. This paper uses electromagnetic transient simulation software to calculate and analyze the overvoltage characteristics and influencing factors of lightning intrusion waves in GIS substations. It studies the effects of lightning current waveform, corona effect, and multiple lightning strikes on the lightning overvoltage. The results show that with the same amplitude of lightning current, the longer the duration and lower the steepness are, the lower the peak and steepness of lightning overvoltage invading the power station will be. As the distance between the lightning strike point and the substation increases, the attenuation effect of corona on lightning overvoltage shows a “not obvious-significant-saturation” pattern. When multiple lightning strikes occur, the peak and steepness of overvoltage caused by the first lightning strike are the highest, and the temperature rise of the lightning arrester varies linearly with the number of lightning strikes.

Simulation Analysis of Corona Pulse Propagation along the Line Based on an Actual Transmission Line

Abstract In the partial discharge test of the shunt reactor of the ultra-high voltage transmission line, the corona discharge caused by high voltage interferes with the test. To further study the propagation rules of the corona pulse on the line side in the transmission line during the ultra-high voltage partial discharge test, based on the parameters of an actual transmission line, the ATP-EMTP electromagnetic simulation software was used for modeling. The propagation rules of corona pulses in the transmission line were analyzed in detail through the simulation model. As the propagation distance increases, different frequency components show different degrees of attenuation. The higher the frequency is, the faster it attenuates.

Design of terahertz metasurface structures for biosensing applications based on deep learning methods

With the advancement of terahertz band applications, extensive research has been conducted on terahertz devices. Terahertz band biosensors find widespread use in biomedical microdetection; however, predicting terahertz spectrum and designing structures pose complex and time-consuming challenges. This article proposes an efficient deep learning method for optimizing the design of terahertz metasurface biosensors. The method employs three neural networks, utilizing spectral response as an intermediary to effectively map customized performance indicators onto geometric structural parameters. Test results demonstrate that the proposed design scheme can generate suitable structural parameters based on the required frequency and bandwidth of the analyte. These output parameters were subsequently simulated and validated using electromagnetic simulation software, yielding results consistent with predictions. This method of using neural networks instead of electromagnetic simulation can be applied to the study of spectrum prediction and inverse design of terahertz devices, providing more possibilities for the future application of terahertz devices.

Designing a High Gain Rectangular Microstrip Patch Antenna Working at 3 GHz for RADAR

This study presents the design and analysis of a microstrip patch antenna optimized for radar applications operating at a frequency of 3 GHz. The antenna is designed to meet the requirements of radar systems, offering characteristics such as high gain, low profile, and broad bandwidth. The design process involves simulation using electromagnetic simulation software to achieve the desired antenna performance parameters. Various antenna parameters, including substrate material selection, patch dimensions, feeding techniques, and impedance matching networks, are carefully optimized to enhance antenna performance. The proposed antenna design is expected to exhibit excellent radiation characteristics, making it suitable for radar applications requiring reliable and efficient communication at 3 GHz frequency. This antenna designed for operating at 3 GHz, type Rogers Ultralam1217 (tm) with dielectric constant, ∈r= 2.2 tanδ (0.0009) and thickness of h = 1.6mm. The antennas are simulated using Ansys HFSS software. The performance is evaluated in terms of return loss, gain, and directivity and is deemed to be compatible with simulations.

Dielectric response characteristics and moisture exposure evaluation of oil-paper insulation based on microstrip ring resonator

Moisture ingress significantly accelerates the aging of oil-paper insulated equipment, making accurate assessment of moisture content critical for the operation and maintenance of oil-immersed insulated power equipment. In this paper, a novel method for rapid moisture content evaluation is proposed based on a microstrip ring resonator (MRR) designed with a fundamental frequency of 1.16 GHz. A calculation model for the dielectric response analysis using MRR is established to characterize dielectric properties of the material layered on the substrate. ANSYS HFSS electromagnetic simulation software was used to study the impact of dielectric material thickness and the substrate on the MRR test results. Experimental measurement demonstrated that the maximum deviation in resonance frequency was merely 0.542 %. The dielectric properties of uniformly and non-uniformly damp insulating pressboard were analyzed across the frequency band from 1 to 6 GHz. The MRR test results were compared with those of the standard resonant cavity method and frequency domain dielectric spectroscopy (FDS) test. Using the regression algorithm and curve analysis, moisture assessment models for both uniformly and non-uniformly damp oil-paper insulation were established. The experimental results show that the MRR test can clearly distinguish between the pressboard samples with varying moisture levels under uniform conditions, with a maximum moisture evaluation error of 8.19 %. The results demonstrate that the MRR test method, requiring only 56 s, can quickly and effectively evaluate the moisture content of insulating pressboard.

Tailored 3D breast models for development of microwave based breast tumor screening

Portable breast monitoring devices, which could be used outside the hospital and even for self-monitoring of risk groups, are considered as promising eHealth applications for future telemedicine. Microwave technique is one of the most promising emerging techniques for portable monitoring devices since it enables low-cost, high accuracy, and user-friendly devices. The technique is based on detecting differences in radio channel responses since tumors have different dielectric properties than the breast glandular or fat tissues. Breast density categories affect the detectability of the tumors with also microwave technique. This paper presents a study on breast tumor detectability with different simulation and measurement models tailored to correspond different breast types. The simulations are carried out using electromagnetic simulation software with human voxel models as well as developed breast models. The evaluation results show that even small-sized breast tumors can be detected with microwave technique within all the breast density categories. Differences in channel responses caused by tumors are breast-type dependent. The results highlight the importance of developing extensive reference databank covering all the breast density categories for microwave-based breast tumor detection applications.

Planar non-contact microwave sensor for the detection of aqueous organic and inorganic samples

In this study, a planar microwave sensor was proposed and manufactured with the aim of detecting and categorizing concentrations of various organic substances, including methanol (CH3OH), ethanol (CH3CH2OH), and 1-butanol (CH3CH2CH2CH2OH), as well as inorganic substances such as sodium carbonate (Na2CO3), potassium carbonate (K2CO3), and sodium hydroxide (NaOH). Throughout the sensor's development, a configuration incorporating a microstrip line and a rectangular patch with a central circular aperture was employed. Full-wave electromagnetic simulation software was utilized to analyze the performance of the sensor in terms of reflection coefficients. The sensor was fabricated using a PCB material with defined properties, which included a dielectric constant of 4.3, a loss tangent of 0.025, and a thickness of 1.6 mm. The reflection coefficient (S11) was measured and analyzed using principal component analysis (PCA) to identify correlations between the classification groups and concentrations of organic and inorganic samples. Additionally, the equivalent circuit has been extracted and modeled to describe the operating mechanism of the microwave sensor. The simulation and measurement results indicate that the sensor is a suitable candidate for the detection and classification of water samples containing CH3OH, CH3CH2OH, CH3CH2CH2CH2OH, Na2CO3, K2CO3, and NaOH. The proposed microwave sensor features a surface area of 29 × 18 mm², leading to a noteworthy reduction in surface utilization compared to other breath biosensors designed for measurement purposes.

Propagation Characteristics and Magnetic Field Distribution of Rotating Magnet-Based Mechanical Antenna in the Air-Seawater-Seabed Three-Layer Medium

Aiming at the application requirements of underwater cross-domain communication, based on the equivalent relationship between the rotating permanent magnet and the orthogonal time-varying current loop, this paper establishes an air-seawater-seabed three-layer medium model and analyzes the magnetic field distribution and propagation characteristics of the rotating permanent magnet-based mechanical antenna (RMBMA). Based on the electromagnetic field simulation software FEKO, the influence of vertical rotation and horizontal rotation of RMBMA on the radiation magnetic field is analyzed. The magnetic field distribution and magnetic field attenuation characteristics of RMBMA at different depths are obtained by simulation. The influence of RMBMA operating frequency and magnetic moment on the propagation characteristics is studied. The research shows that the horizontal rotation of the magnetic source is better than the vertical rotation in the long-distance underwater communication. When the magnetic source and the receiving point are close to the interface of the medium, the magnetic field strength and the propagation distance can be relatively increased. With appropriate frequency and magnetic moment, the magnetic field strength and communication distance can be further increased.

Research on transmission and crosstalk characteristics of a new type of through silicon via and multilayer through silicon via

In this work, a new type of bar-coaxial ring TSV (B-coaxial ring TSV) structure was proposed. This study used three-dimensional electromagnetic simulation software for analysis. Firstly, the conventional Bar-TSV (B-TSV) structure and the B-coaxial ring TSV structure were modeled, and their S-parameter results were compared. Our results indicated that the B-coaxial ring TSV structure had better transmission characteristics and crosstalk resistance. Secondly, by simulating of the B-coaxial ring TSV structure and the coaxial ring-tapered TSV structure, we proposed how to choose different structures for different application scenarios. Thirdly, the influence of some structural parameters of the B-coaxial ring TSV structure on the transmission performance was studied. Finally, the multilayer TSV structures of conventional B-TSV, B-coaxial ring TSV and coaxial ring-tapered TSV were studied respectively, and their performance was compared and analyzed.

Strong circular dichroism absorbers using chiral metamaterials with circular polarization

We designed and characterized a chiral metamaterial circularly polarized strong circular dichroism absorber with dynamic tuning capabilities using graphene. The synergistic combination of strong circular dichroism and perfect absorption, coupled with the tunability afforded by graphene, positions this absorber as a promising candidate for advanced electromagnetic applications. Employing a frequency-domain solver in electromagnetic simulation software, the impact of parameters such as the thickness of a metal U-ring, a silica dielectric layer, and the polarization angle of incident light on circular dichroism is systematically analyzed. Strong circular dichroism can be achieved by adjusting the misalignment angle of the metal U-ring, reaching a value as high as 0.91. At an incident angle of 60°, left-circularly polarized (LCP) light demonstrates outstanding wide-angle absorption performance, absorbing over 80% in the x-z plane and more than 70% in the y-z plane. Transitioning from circular to linear polarization and changing the tilt angle of the metal U-ring also achieves a 99.99% absorption peak at 1.33 THz. Moreover, in comparison to conventional absorbers, the structure presented in this study offers enhanced controllability of absorption performance through external voltage manipulation. This research not only refines the existing concepts but also introduces novel ideas for the development of tunable chiral optical devices.

Electromagnetic Environment Assessment and Safety Research of Electrified High-Speed Railway Carriages

With the advent of modern, high-speed electrified rail systems, there has been increasing concern about electromagnetic safety in rail carriages. The aim of this study was to assess the electromagnetic safety of passengers on trains by utilizing advanced 3D electromagnetic simulation software. A comprehensive model of the electromagnetic environment experienced by passengers on a CR400AF train, specifically under the influence of catenary radiation, was constructed. We analyzed the magnetic field strength, electric field strength, and current density in the brains of 20 passengers in various positions in the train. The findings revealed that among the 20 passengers analyzed, the maximum and minimum magnetic induction intensity recorded in the brain were 8.41 and 0.01 μT, respectively. The maximum and minimum induced electric field intensities were 1110 and 10 μV/m, respectively. Lastly, the maximum and minimum induced current densities were 1200 and 10 μA/m2, respectively. The results show that when people ride on the CR400AF train, the magnetic induction intensity, induced electric field strength, and induced current density in the brain are below the recommended basic limits of exposure to power frequency electromagnetic fields in the guidelines of the International Committee on Non-Ionizing Radiation Protection. The power frequency magnetic field generated by the catenary can be effectively shielded by the aluminum alloy car body. The final result of this study indicates that the electromagnetic exposure from the contact wire at the level 25 kV does not pose a threat to the health of passengers on the CR400AF train.

Application of Pathfinding Algorithms in Partial Discharge Localization in Power Transformers.

The introduction of artificial intelligence (AI) to ultra-high-frequency (UHF) partial discharge (PD) monitoring systems in power transformers for the localization of PD sources can help create a robust and reliable system with high usability and precision. However, training the AI with experimental data or data from electromagnetic simulation is costly and time-consuming. Furthermore, electromagnetic simulations often calculate more data than needed, whereas, for localization, the signal time-of-flight information is the most important. A tailored pathfinding algorithm can bypass the time-consuming and computationally expensive process of simulating or collecting data from experiments and be used to create the necessary training data for an AI-based monitoring system of partial discharges in power transformers. In this contribution, Dijkstra's algorithm is used with additional line-of-sight propagation algorithms to determine the paths of the electromagnetic waves generated by PD sources in a three-dimensional (3D) computer-aided design (CAD) model of a 300 MVA power transformer. The time-of-flight information is compared with results from experiments and electromagnetic simulations, and it is found that the algorithm maintains accuracy similar to that of the electromagnetic simulation software, with some under/overestimations in specific scenarios, while being much faster at calculations.

A systematic approach for the development of wide band band pass filters using resonators

In this paper, for the first time a novel and systematic approach is presented to construct a wideband Band Pass Filters (BPFs) with high selectivity and stopband response. Two BPFs (Filter I and Filter II) were built on a Taconic (TLX-9) substrate using semi-circular tapered coupled lines, Defected Microstrip Structures (DMSs), Defected Ground Structures (DGS), and Stepped Impedance Resonators (SIRs). The precision of the design procedure is confirmed through 3-D full wave Electro-Magnetic (EM) simulation software where two wideband filters were designed for L, S, and C-bands. Additionally, parametric analysis has been done to evaluate the performance of both wideband filters with key features such as return loss, insertion loss, Band Width (BW), selectivity, and stopband response. Even-odd mode analysis has been implemented using the ABCD matrix that acts as a source for mathematical analysis of Filter I. Eventually, two wideband filters have been fabricated and tested for their effectiveness, and the measured results of two wideband filters are in line with the simulated ones with slight deviations due to fabrication tolerances and connector losses. The prototyped Filter I functions as a bandpass in the frequency range of 2.4 GHz to 4.8 GHz with a maximum insertion loss of 0.85 dB and return loss of 19.5 dB thereby providing 64% Fractional Band Width (FBW). Near 19 dB rejection is observed in the lower and upper stopband regions with BW (stopbands) greater than 2 GHz. Moreover, Filter II is also fabricated and tested. The experimental return loss of 20 dB and insertion loss (maximum) of 0.73 dB over the passband (1.9 GHz to 3.4 GHz) were found with 0.7 Selectivity Factor (SF). More than 20 dB attenuation of stopbands (lower and upper) was achieved. Thus, the fabricated wideband BPFs operate in L, S, and C-bands for radars, satellite and long-distance radio communications, and military telemetry applications.

WLAN monopole antenna design by Siamese convolutional neural network and KNN exploiting Gaussian process

In the process of antenna design, surrogate models can generally be used, but modeling requires a large number of samples. Although full wave electromagnetic simulation software can handle this task, obtaining a large number of samples is time-consuming, however too small number of sample may lead to lower accuracy of the trained surrogate model. Inspired by semi-supervised learning methods, this paper uses Siamese convolutional neural networks (SCNN) and K-nearest neighbor (KNN) algorithms to generate highly reliable virtual samples and expand the training sample set, further improving the accuracy and robustness of the surrogate model by exploiting Gaussian process (GP) models. The proposed method is named SCNN-KNN-GP, which is used for the design of WLAN dual band monopole antennas. Moreover, the relationships between the performance of the proposed model and the increased number of virtual samples and the coefficient of the KNN are studied, resulting in a more excellent surrogate model structure.

The enhancing energy efficiency in hyperthermia treatment: a frequency-reconfigurable L-Shape antenna design and analysis

The object of research is a frequency-reconfigurable L-Shape antenna. This paper presents an innovative study focusing on the design and analysis of a frequency-reconfigurable L-Shape antenna with a specific application in Hyperthermia Treatment. The antenna, operating in the frequency range of 2.5 to 8 GHz, utilizes a varactor to achieve agility and simplify design, thereby reducing component count. Constructed with a Roggers RT5880 (lossy) substrate, the L-Shape configuration ensures optimal performance. The incorporation of a single varactor, acting as a junction capacitance, not only enables straightforward tuning but also contributes to enhanced energy efficiency by reducing overall power consumption in the reconfigurable antenna system. The study employed CST Microwave Studio's 3D Electromagnetic field simulation software for time domain solver-based simulations, with validation conducted using the frequency domain solver. Results from the simulations showcase the antenna's performance at different frequency states. At the tuning state frequency of 2.7 GHz, the antenna exhibits an impressive gain of 1.905 dB and a directivity of 7.530 dB. Similarly, at the tuning state frequency of 6.89 GHz, the gain is measured at 6.806 dB with a directivity of 7.490 dB. The proposed L-Shape antenna design not only demonstrates significant potential for Hyperthermia Treatment, allowing targeted heating within the 2.5 to 8 GHz frequency range but also aligns with the multidisciplinary focus of medical science. This contribution reflects the commitment to advancing medical science through original research, fostering innovation, and promoting energy-efficient solutions with practical applications in clinical settings.

ÇİFT-BANT İRİS POLARİZÖR TASARIM VE OPTİMİZASYONU

The structure that transforms a linear polarized signal into right-hand or left-hand circularly polarized signals is called a polarizer. In this study, a dual-band waveguide polarizer used in satellite communications is presented. The waveguide polarizer is designed using iris structures on a square waveguide. The purpose of the polarizer is to transmit the ±45° tilted linearly polarized signal at its input to the output as a right-hand or left-hand circularly polarized wave, and vice versa. At the input of the polarizer, a transition is designed between the WR42 waveguide and the square waveguide. At the output stage, a transition from square waveguide to circular waveguide is designed. In this paper, the design steps of both the polarizer and the transition sections, the optimization parameters, and simulation results are presented in full detail. The simulations are performed with a commercial electromagnetic simulation software, CST Studio Suite. The design operates within the Ka-band, specifically at 17.2 – 21.2 GHz and 27.5 – 31 GHz frequency bands. The insertion loss of the iris polarizer is 23 dB, and the phase difference is less than 15° around 90° for both bands.

Characteristic Mode Analysis Based Highly Flexible Antenna For Millimeter Wave Wireless Applications

The millimeter wave spectrum fulfills the demand for higher data rates with low latency. Moreover, futuristic wearable gadgets demand flexible antennas operating at these frequencies, such that they can easily be accommodated. Therefore, the article focuses on designing a compact and highly flexible antenna with the aid of characteristic mode analysis (CMA). A thin polyimide substrate of 0.1 mm thickness is used to maintain flexibility. The overall antenna profile is 0.61λ0×0.61λ0\\documentclass[12pt]{minimal} \\usepackage{amsmath} \\usepackage{wasysym} \\usepackage{amsfonts} \\usepackage{amssymb} \\usepackage{amsbsy} \\usepackage{mathrsfs} \\usepackage{upgreek} \\setlength{\\oddsidemargin}{-69pt} \\begin{document}$$0.61{\\lambda }_{0} \ imes 0.61{\\lambda }_{0}$$\\end{document}. The design evolves through four stages, where, in each stage, the solution to the surface current through eigenvalue leads to significant modes. The final stage design generated Mode 2 fundamental mode at 30.5 GHz along with contributing Modes 3 and 5 with a bandwidth range of 28-31.5 GHz. Further, the design is simulated using electromagnetic simulation software, and the prototype is fabricated. The simulated and measured reflection coefficient |S11| > 10 dB in 28.72-32 GHz and 28.9-31.75 GHz. The CMA analyzed, simulated, and measured gain is 4.82 and 5.6 dBi, respectively. The proposed antenna has a stable response for conformal orientations along the x and y-axis. The antenna has resulted in bidirectional radiation in the XZ plane with simulated and measured half-power-beam-width (HPBW) of 58° and 54°. In the YZ plane, it resulted in omnidirectional radiation. The simulated and measured results are in good agreement. The article also performs the link budget analysis. It suggested that the antenna can communicate 100 Mbps of data to a distance of 100 m and 1 Gbps of data up to 70 m. Thus, the proposed antenna structure is suitable for wearable, IoT, and other 5G wireless applications.