International Journal of Numerical Modelling-Electronic Networks Devices and Fields最新文献

{"title":"A Novel Method of Accurate Calculation of the Magnetic Dipole Field in Both the Near and Far Fields","authors":"Jiaqi Liu,&nbsp;Guoqiang Wang,&nbsp;Chaobo Liu,&nbsp;Qiancheng Zhang,&nbsp;Lifei Meng,&nbsp;Zhong Yi,&nbsp;Qi Xiao,&nbsp;Tielong Zhang","doi":"10.1002/jnm.70068","DOIUrl":"https://doi.org/10.1002/jnm.70068","url":null,"abstract":"<div>\u0000 \u0000 <p>The magnetic dipole serves as a fundamental concept in understanding electromagnetic phenomena. It has extensive applications across various fields such as geophysics and indoor navigation, which require accurate determination of its magnetic field. Although the magnetic dipole approximation yields satisfactory results in the far field, its computational accuracy is poor in the near-field region. Here, we propose a method of accurately calculating the magnetic dipole field in both the near and far fields. This method encompasses three steps: first, calculating the magnetic field strength <i>B</i>_<i>T</i> at the position <b>r</b>; second, determining the direction of the magnetic field at <b>r</b>; and third, calculating three components of the magnetic field. Numerical tests show that the calculation error of <i>B</i>_<i>T</i> is &lt; 1% at <i>r</i> &gt; 1.2 <i>R</i>, and is &lt; 0.1% at <i>r</i> &gt; 10 <i>R</i>, where <i>R</i> is the radius of the magnetic dipole. Additionally, the magnetic field direction can be precisely modeled via multi-parameter fitting, yielding angular errors &lt; 0.1° in most regions at <i>r</i> &gt; 1.2 <i>R</i>. Integration of the direction and <i>B</i>_<i>T</i> enables us to accurately calculate three components of the magnetic field with an error of &lt; 1% at <i>r</i> &gt; 1.8 <i>R</i>. These results indicate that our method is able to achieve high accurate calculation of the magnetic dipole field in both the near and far fields. This method can provide an effective computational algorithm for the applications relying on magnetic dipoles.</p>\u0000 </div>","PeriodicalId":50300,"journal":{"name":"International Journal of Numerical Modelling-Electronic Networks Devices and Fields","volume":"38 3","pages":""},"PeriodicalIF":1.6,"publicationDate":"2025-06-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144264399","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Enhanced Pixel Antenna Design and Optimization Through Dynamic Updating of Initial Structure","authors":"Fan Jiang,&nbsp;Huiyao Tan,&nbsp;Lulu Chen,&nbsp;Liang Hua Ye,&nbsp;Jian-Feng Li,&nbsp;Duo-Long Wu","doi":"10.1002/jnm.70067","DOIUrl":"https://doi.org/10.1002/jnm.70067","url":null,"abstract":"<div>\u0000 \u0000 <p>Dynamic updating technique for initial structure in pixel antenna design and optimization is proposed. The conventional approach to pixel antenna design employs a fixed initial pixel structure set at the start of the entire process, while rarely studying the setting of the initial structure; therefore, the performance potential is not fully exploited. The proposed approach adaptively updates the initial structure to enhance the performance of the pixel antenna design, aiming to find the optimal initial pixel structure that achieves miniaturization and broadband capabilities. In general, the design procedure starts with an initial structure with relatively big element size and small overall size, then gradually reduces the element size and expands the overall size of the pixel area. A two-port pixel antenna is used as a design example to validate the proposed updating technique. The goal was to design a dual-port pixel antenna operating in the band of 2.4–3.2 GHz, using a miniaturized size. After two rounds of updates, the obtained −10 dB impedance bandwidths increased from 0.44 GHz (2.47–2.91GHz) to 0.75 GHz (2.45–3.20 GHz) and to 1.07 GHz (2.35–3.42 GHz), while having isolation better than −15 dB. The statistical results of 10 optimization runs for 3 initial structures also showed the performance enhancement of each updated initial structure. The proposed updated technology can be applied to other types of pixel antenna designs, with different design specifications.</p>\u0000 </div>","PeriodicalId":50300,"journal":{"name":"International Journal of Numerical Modelling-Electronic Networks Devices and Fields","volume":"38 3","pages":""},"PeriodicalIF":1.6,"publicationDate":"2025-06-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144244477","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"A Hyperaccurate Semi–Analytical Method With Error Bound Analysis for Treating Fractional Integral Equations With Functional Kernels and Variable Delays","authors":"Ömür Kıvanç Kürkçü","doi":"10.1002/jnm.70061","DOIUrl":"https://doi.org/10.1002/jnm.70061","url":null,"abstract":"<div>\u0000 \u0000 <p>This study is concerned with treating the fractional integral equations with functional kernels and variable delays, introducing a hyperaccurate semi–analytical method based on the Stieltjes–Wigert polynomials, matrix expansions, and the Laplace transform. After analytically converting the terms in the governing equation into the matrix expansions of the Stieltjes–Wigert polynomials type at the collocation points, the method gathers these matrices into a unique matrix equation and then readily solves it by an elimination technique. The residual improvement technique is also introduced to correct the obtained solutions. The residual error bound analysis is theoretically proved via algebraical properties and the mean value theorem for fractional integral calculus, respectively. Six model equations are treated via the method, which runs on a devised computer program. Based on the outcomes, the method is straightforward to treat model equations and to encode its mainframe on a mathematical software.</p>\u0000 </div>","PeriodicalId":50300,"journal":{"name":"International Journal of Numerical Modelling-Electronic Networks Devices and Fields","volume":"38 3","pages":""},"PeriodicalIF":1.6,"publicationDate":"2025-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144206927","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"An Accurate Dynamic Model Identification Method for Industrial Robots Based on Improved Excitation Trajectory","authors":"Xiao Lin,&nbsp;Junyang Li,&nbsp;Yankui Song,&nbsp;Yogendra Arya,&nbsp;Yu Xia","doi":"10.1002/jnm.70062","DOIUrl":"https://doi.org/10.1002/jnm.70062","url":null,"abstract":"<div>\u0000 \u0000 <p>This article focuses on dynamic parameter identification for industrial robots and proposes a parameter identification method based on an improved excitation trajectory. First, a complex nonlinear friction model is adopted and modified according to joint friction characteristics, with a genetic algorithm utilized to determine its six parameters. Second, a weighted optimal excitation trajectory is designed to address nonlinear friction requirements and smooth operation constraints. Then, a global parameter optimization algorithm based on the least squares method and the modified sparrow search algorithm is proposed. Finally, the proposed method is validated on a self-developed six-axis industrial robot. Experimental results demonstrate that the proposed method achieves higher identification accuracy compared with two representative identification approaches.</p>\u0000 </div>","PeriodicalId":50300,"journal":{"name":"International Journal of Numerical Modelling-Electronic Networks Devices and Fields","volume":"38 3","pages":""},"PeriodicalIF":1.6,"publicationDate":"2025-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144206928","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Special Issue: The 13th International Symposium on Electric and Magnetic Fields (EMF 2023)","authors":"Christophe Geuzaine,&nbsp;André Nicolet","doi":"10.1002/jnm.70066","DOIUrl":"https://doi.org/10.1002/jnm.70066","url":null,"abstract":"<p>On behalf of the Editorial Board, we are pleased to present a selection of papers related to the 13th International Symposium on Electric and Magnetic Fields (EMF 2023), held in Marseille, France, on August 29–31, 2023.</p><p>The EMF symposium series, whose first edition was held in Liège, Belgium, in 1992, aims at building a bridge between recent research advances in mathematical and numerical modeling of electromagnetic fields and the growing number of industrial problems requiring such techniques. The 13th edition was organized at Aix-Marseille Université and attracted 75 participants from 16 countries.</p><p>Among the 65 presentations in the symposium program, 13 papers were selected for publication in this special issue of the <i>International Journal of Numerical Modelling: Electronic Networks, Devices and Fields</i>. The high scientific and technical quality of the symposium is well reflected in the quality of the manuscripts contained in this special issue.</p><p>Three broad topics were covered during the 13th edition of the symposium. The first major topic considers the mathematical modeling of electromagnetic problems in view of their eventual numerical solution on computers, with contributions on the calculation of forces [<span>1</span>], homogenization [<span>2</span>] and material models [<span>3, 4</span>]. The second major topic treats general methodological advances in numerical methods, from quasi-static [<span>5, 6</span>] to high-frequency problems [<span>7, 8</span>]. The third major topic is the application of modeling to the study, design, and optimization of a wide range of technological devices, spanning low- to high-frequency electromagnetic regimes [<span>9-13</span>]. This underlines the spirit of the conference, which encompasses both theory and practical applications.</p><p>We express our gratitude to the members of the EMF scientific committee—Florian Bentivegna, Oszkár Bró, Markus Clemens, Stéphane Clénet, Willie Cronje, Luc Dupré, Johan Gyselinck, Kay Hameyer, Lauri Kettunen, Vincent Mazauric, Gérard Meunier, Axel Modave, Ronan Perrussel, Martin Petrun, Adel Razek, Maurizio Repetto, Ruth Sabariego, Sebastian Schöps, Jan Sykulski—as well as to all the reviewers who provided the necessary volunteer time and expertise to conduct a fair and detailed review, ensuring high publication standards for the selected manuscripts. We also thank the staff from the <i>Association des Ingénieurs de Montefiore</i> (AIM), and especially Céline Dizier and Louisa Kara, for their help organizing the EMF symposium series.</p><p>We hope that you will enjoy reading this selection of articles.</p>","PeriodicalId":50300,"journal":{"name":"International Journal of Numerical Modelling-Electronic Networks Devices and Fields","volume":"38 3","pages":""},"PeriodicalIF":1.6,"publicationDate":"2025-06-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://onlinelibrary.wiley.com/doi/epdf/10.1002/jnm.70066","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144206877","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"OA","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Long Short-Term Memory (LSTM)-Based Modeling of Negative Bias Temperature Instability (NBTI) in 40 nm MOSFETs","authors":"Fikret Başar Gencer,&nbsp;Xhesila Xhafa,&nbsp;Ali Doğuş Güngördü,&nbsp;Mustafa Berke Yelten","doi":"10.1002/jnm.70059","DOIUrl":"https://doi.org/10.1002/jnm.70059","url":null,"abstract":"<div>\u0000 \u0000 <p>Bias temperature instability (BTI) is a time-based degradation mechanism that causes serious damage to the performance of analog and digital integrated circuits. The increasingly probabilistic nature of this phenomenon renders machine learning-based modeling approaches more advantageous, as they can deliver more accurate results in that context compared to analytical methods. In this paper, the Long Short-Term Memory (LSTM) method, a time-series approach, has been adopted to model BTI in 40 nm CMOS p-type metal-oxide-semiconductor field-effect transistors (MOSFETs). The aging model has been established by training the experimental data collected from a dedicated test chip. A bi-directional LSTM structure has been employed in model generation. Mean-square error (MSE) results indicate that the model can be effectively utilized in interpolation exercises where the test data falls within the same interval as the training data, with great accuracy. Moreover, the model has yielded promising outcomes in extrapolation exercises where the test data lies outside the defined training range. This property potentially qualifies the proposed approach for time-to-market and cost-reduction efforts.</p>\u0000 </div>","PeriodicalId":50300,"journal":{"name":"International Journal of Numerical Modelling-Electronic Networks Devices and Fields","volume":"38 3","pages":""},"PeriodicalIF":1.6,"publicationDate":"2025-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144190878","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Design of Compact and Quad Band Gap Coupled Ring-Shape Microstrip Patch Antenna for WLAN/ISM/WiMAX/5G Applications","authors":"Surjeet Raikwar,&nbsp;Akanksha Gupta,&nbsp;Karunesh Srivastava,&nbsp;Maninder Singh,&nbsp;Nishant Anand,&nbsp;Ramesh Kumar Verma","doi":"10.1002/jnm.70060","DOIUrl":"https://doi.org/10.1002/jnm.70060","url":null,"abstract":"<div>\u0000 \u0000 <p>In this paper, a gap coupled ring-shape multi-band antenna of quad-band characteristics has been designed. The geometry of the proposed gap coupled ring-shape antenna is obtained by loading two horizontal and six vertical strips of the same width and the same gap. The quad band characteristic of the proposed antenna is obtained at frequencies 2.48, 3.85, 5.14, and 5.61 GHz. The quad band lies within frequency ranges 2.34–2.59 GHz (first band), 3.56–4.06 GHz (second band), 5.09–5.21 GHz (third band) and 5.47–5.96 GHz (fourth band). The second and fourth bands of the antenna arise due to outer vertical strips, while the first and third bands of the antenna are due to middle and inner vertical strips, respectively. The return loss of −17.31, −29.18, −18.40, and − 19.19 dB is obtained at frequencies 2.48, 3.85, 5.14, and 5.61 GHz, respectively. Additionally, a parametric analysis is also conducted to enhance the performance of the proposed gap coupled antenna. To validate the geometry of the proposed antenna, experimental measurement is performed with the prototype antenna. The first band (2.34–2.59 GHz) of the antenna covers WLAN, ISM band, and WiMAX; the second band (3.56–4.06 GHz) of the antenna covers 5G; the third band (5.09–5.21 GHz) of the antenna covers WLAN; and the fourth band (5.47–5.96 GHz) of the antenna covers WiMAX and WLAN applications. The proposed quad band antenna is a cost-effective and efficient solution for multi-band communication devices. It eliminates the need for multiple antennas and lowers hardware costs.</p>\u0000 </div>","PeriodicalId":50300,"journal":{"name":"International Journal of Numerical Modelling-Electronic Networks Devices and Fields","volume":"38 3","pages":""},"PeriodicalIF":1.6,"publicationDate":"2025-06-02","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144197526","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Wearable Textile Antenna With Low SAR and High Fidelity for BAN and Medical Applications","authors":"Raghav Dwivedi,&nbsp;D. K. Srivastava,&nbsp;Vinod Kumar Singh","doi":"10.1002/jnm.70058","DOIUrl":"https://doi.org/10.1002/jnm.70058","url":null,"abstract":"<div>\u0000 \u0000 <p>This paper presents a novel wearable antenna fabricated using denim material, designed for flexible electronics and medical monitoring applications. The proposed antenna leverages common jean fabric as the substrate material, offering a cost-effective and readily available solution while combining esthetic appeal with practical functionality through its unique configuration. Operating across 2.269–19.42 GHz with a maximum gain of 6.75 dB, the antenna achieves an enhanced bandwidth of 158.15%. Notably, the design measured as 0.488<i>λ</i>_o <b>×</b> 0.488<i>λ</i>_o × 0.008<i>λ</i>_o exhibits a low specific absorption rate (SAR) compared to FCC standards that is 1.6 W/kg averaged over 1 g of tissue, making it particularly suitable for medical monitoring applications. We obtained a maximum SAR value for the antenna as 1.61, 1.01 W/kg for 1 and 10 g at 2 mm from the body phantom, 0.488 and 0.769 W/kg for 1 and 10 g when placed at 5 mm from the human phantom, and 1.02, 0.73 W/kg for 1 and 10 g at on-body placement of the antenna. Experimental results demonstrate the antenna's effectiveness for vital signs surveillance while maintaining wearer safety and comfort. The use of denim as the substrate material not only ensures flexibility and durability but also provides an eco-friendly approach by utilizing common textile materials. The high-fidelity factor and wideband characteristics ensure reliable data transmission, making this design a promising solution for next-generation wearable healthcare devices.</p>\u0000 </div>","PeriodicalId":50300,"journal":{"name":"International Journal of Numerical Modelling-Electronic Networks Devices and Fields","volume":"38 3","pages":""},"PeriodicalIF":1.6,"publicationDate":"2025-05-29","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144171436","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"Bernoulli Collocation Method for Solving Time-Fractional Diffusion Equation Arising in Physics","authors":"Jalil Rashidinia,&nbsp;Arefeh Momeni","doi":"10.1002/jnm.70052","DOIUrl":"https://doi.org/10.1002/jnm.70052","url":null,"abstract":"<div>\u0000 \u0000 <p>This research presents an effective spectral collocation scheme based on orthogonalized Bernoulli polynomials for solving the time-fractional diffusion equation (TFDE). To provide a numerical method, we consider the Bernoulli polynomials and estimate the derivatives as well as the Caputo fractional derivative by operational matrices. By collocating the discretized equations, we obtain a system of algebraic equations. By solving this system, we obtain the approximate solution. The advantages of the suggested method are its low computational cost and exponential convergence. Also, the convergence analysis of the presented method is discussed. Finally, we present several test problems to demonstrate the capability of the proposed method. The obtained results are compared with the existing methods in the literature.</p>\u0000 </div>","PeriodicalId":50300,"journal":{"name":"International Journal of Numerical Modelling-Electronic Networks Devices and Fields","volume":"38 3","pages":""},"PeriodicalIF":1.6,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144140553","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}

{"title":"New Technique Based on Vieta–Lucas Polynomials for Solving Nonlinear Stochastic Itô-Volterra Integral Equation","authors":"Narges Barzegar,&nbsp;Farshid Mirzaee,&nbsp;Erfan solhi","doi":"10.1002/jnm.70044","DOIUrl":"https://doi.org/10.1002/jnm.70044","url":null,"abstract":"<div>\u0000 \u0000 <p>In the present study, we introduce an iterative technique grounded in shifted Vieta–Lucas polynomials for the numerical solution of nonlinear stochastic Volterra integral equations. Notably, our iterative approach is fast and provides solutions without solving algebraic equations. This method addresses nonlinear problems with high accuracy, making it very useful. We present an error estimation for the suggested approach, theoretically confirming its accuracy. Several numerical examples illustrate the practicality and efficacy of our technique. Furthermore, we compare the numerical outcomes of our method with those reported in existing literature and, whenever available, with exact solutions. This comparative analysis affirms the practicality and high precision of the suggested approach.</p>\u0000 </div>","PeriodicalId":50300,"journal":{"name":"International Journal of Numerical Modelling-Electronic Networks Devices and Fields","volume":"38 3","pages":""},"PeriodicalIF":1.6,"publicationDate":"2025-05-26","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"144140368","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":4,"RegionCategory":"工程技术","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}