Pub Date : 2023-10-23DOI: 10.1109/JMMCT.2023.3326774
Chang Yang;Dan Jiao
In this work, we develop a kernel-independent and purely algebraic method, Nested Construction Method, which can construct a rank-minimized ${mathcal H}^{2}$ -matrix with low complexity based on prescribed accuracy. The time cost of this method in generating each cluster basis and coupling matrix is of $O(k n log {n})$ , while the memory consumption scales as $O(k^{2})$ , where $k$ is the rank of the cluster basis, and $n$ is cluster size. The accuracy and efficiency of the proposed method are demonstrated by extensive numerical experiments. In addition to surface integral equations, the proposed algorithms can also be applied to solving other electrically large integral equations.
在这项工作中，我们开发了一种核无关的纯代数方法，即嵌套构造方法，它可以在规定精度的基础上构造一个低复杂度的秩最小化${mathcal H}^{2}$-矩阵。该方法生成每个簇基和耦合矩阵的时间成本为$O(k n log {n})$，而内存消耗为$O(k^{2})$，其中$k$为簇基的秩，$n$为簇大小。大量的数值实验证明了该方法的准确性和有效性。除了曲面积分方程外，所提出的算法也可应用于求解其他大型电积分方程。
{"title":"Algebraic and Fast Nested Construction Method for Generating Rank-Minimized ${mathcal H}^{2}$-Matrix for Solving Electrically Large Surface Integral Equations","authors":"Chang Yang;Dan Jiao","doi":"10.1109/JMMCT.2023.3326774","DOIUrl":"10.1109/JMMCT.2023.3326774","url":null,"abstract":"In this work, we develop a kernel-independent and purely algebraic method, Nested Construction Method, which can construct a rank-minimized \u0000<inline-formula><tex-math>${mathcal H}^{2}$</tex-math></inline-formula>\u0000-matrix with low complexity based on prescribed accuracy. The time cost of this method in generating each cluster basis and coupling matrix is of \u0000<inline-formula><tex-math>$O(k n log {n})$</tex-math></inline-formula>\u0000, while the memory consumption scales as \u0000<inline-formula><tex-math>$O(k^{2})$</tex-math></inline-formula>\u0000, where \u0000<inline-formula><tex-math>$k$</tex-math></inline-formula>\u0000 is the rank of the cluster basis, and \u0000<inline-formula><tex-math>$n$</tex-math></inline-formula>\u0000 is cluster size. The accuracy and efficiency of the proposed method are demonstrated by extensive numerical experiments. In addition to surface integral equations, the proposed algorithms can also be applied to solving other electrically large integral equations.","PeriodicalId":52176,"journal":{"name":"IEEE Journal on Multiscale and Multiphysics Computational Techniques","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-10-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"135152772","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-10-09DOI: 10.1109/JMMCT.2023.3321123
Daria E. Titova
Rotating cavities are often used for rotation rate measurement. However, the representation of electromagnetic fields in rotating reference frames is based on simplifying assumptions and approximate solutions. In this article, problem of excitation of electromagnetic field inside a rotating spherical cavity resonator with arbitrary sources of currents and charges is formulated and solved rigorously. The solution is based on the covariant Maxwell's equations. Expressions for the electromagnetic field components are derived using electric and magnetic Debye potentials. Impedance boundary problem of electromagnetic field excitation in a rotating dielectric filled spherical cavity with finite conductivity metal walls is formulated and solved rigorously. In a special case of excitation of the cavity resonator with an elementary electric dipole, the frequency response and the quality factor of the resonator were calculated for different dielectric fillings and metals of the cavity walls. The obtained analytical solutions were verified for the special case of zero rotation rate compared with the simulation of the problem in CAD.
{"title":"Excitation of Electromagnetic Field Inside Rotating Spherical Cavity","authors":"Daria E. Titova","doi":"10.1109/JMMCT.2023.3321123","DOIUrl":"https://doi.org/10.1109/JMMCT.2023.3321123","url":null,"abstract":"Rotating cavities are often used for rotation rate measurement. However, the representation of electromagnetic fields in rotating reference frames is based on simplifying assumptions and approximate solutions. In this article, problem of excitation of electromagnetic field inside a rotating spherical cavity resonator with arbitrary sources of currents and charges is formulated and solved rigorously. The solution is based on the covariant Maxwell's equations. Expressions for the electromagnetic field components are derived using electric and magnetic Debye potentials. Impedance boundary problem of electromagnetic field excitation in a rotating dielectric filled spherical cavity with finite conductivity metal walls is formulated and solved rigorously. In a special case of excitation of the cavity resonator with an elementary electric dipole, the frequency response and the quality factor of the resonator were calculated for different dielectric fillings and metals of the cavity walls. The obtained analytical solutions were verified for the special case of zero rotation rate compared with the simulation of the problem in CAD.","PeriodicalId":52176,"journal":{"name":"IEEE Journal on Multiscale and Multiphysics Computational Techniques","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-10-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68175802","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-07DOI: 10.1109/JMMCT.2023.3312756
Chang Che;Yi Zeng;Ming Yu
This article proposes a novel multiphysics design methodology for a U-band bandstop waveguide filter with temperature compensation (TC). A bimetal TC structure is first implemented to a bandstop filter in such high frequencies for working in a wide temperature range (−20 °C ∼ 70 °C) with little frequency drift. The synthesis and design of the bandstop filter are detailed. The proposed methodology mainly guides the design of the bimetal actuator from geometry, multiphysics, post-production and theoretical promotion. The geometric derivation for the bimetal reactions is elaborated and leads to a simplified equivalent model. Multiphysics analysis, including temperature, thermal stress, and electromagnetic field, is co-elaborated in the design process. Considering the fabrication errors, a post-production adjustment method for the TC structure is designed for practical use. Dimensionless formulae are introduced to provide general design guidelines and rules for filters with different dimensions and TC demands. Finally, a sixth-order temperature-compensated bandstop filter is manufactured and tested in temperature cycles. The measurements have validated the theoretical and simulation results.
{"title":"Multiphysics Design Methodology for U-Band Temperature-Compensated Bandstop Filters","authors":"Chang Che;Yi Zeng;Ming Yu","doi":"10.1109/JMMCT.2023.3312756","DOIUrl":"https://doi.org/10.1109/JMMCT.2023.3312756","url":null,"abstract":"This article proposes a novel multiphysics design methodology for a U-band bandstop waveguide filter with temperature compensation (TC). A bimetal TC structure is first implemented to a bandstop filter in such high frequencies for working in a wide temperature range (−20 °C ∼ 70 °C) with little frequency drift. The synthesis and design of the bandstop filter are detailed. The proposed methodology mainly guides the design of the bimetal actuator from geometry, multiphysics, post-production and theoretical promotion. The geometric derivation for the bimetal reactions is elaborated and leads to a simplified equivalent model. Multiphysics analysis, including temperature, thermal stress, and electromagnetic field, is co-elaborated in the design process. Considering the fabrication errors, a post-production adjustment method for the TC structure is designed for practical use. Dimensionless formulae are introduced to provide general design guidelines and rules for filters with different dimensions and TC demands. Finally, a sixth-order temperature-compensated bandstop filter is manufactured and tested in temperature cycles. The measurements have validated the theoretical and simulation results.","PeriodicalId":52176,"journal":{"name":"IEEE Journal on Multiscale and Multiphysics Computational Techniques","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-09-07","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49962814","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-09-04DOI: 10.1109/JMMCT.2023.3311322
Yang Liu;Tianhuan Luo;Aman Rani;Hengrui Luo;Xiaoye Sherry Li
This article presents a computationally efficient framework for identifying resonance modes of 3D radio-frequency (RF) cavities with damping waveguide ports. The proposed framework relies on surface integral equation (IE) formulations to convert the task of resonance detection to the task of finding frequencies at which the lowest few eigenvalues of the system matrix is close to zero. For the linear eigenvalue problem with a fixed frequency, we propose leveraging fast direct solvers to efficiently invert the system matrix; for the frequency search problem, we develop a hybrid optimization algorithm that combines Bayesian optimization with down-hill simplex optimization. The proposed IE-based resonance detection framework (IERD) has been applied to detection of high-order resonance modes (HOMs) of realistic accelerator RF cavities to demonstrate its efficiency and accuracy.
{"title":"Detecting Resonance of Radio-Frequency Cavities Using Fast Direct Integral Equation Solvers and Augmented Bayesian Optimization","authors":"Yang Liu;Tianhuan Luo;Aman Rani;Hengrui Luo;Xiaoye Sherry Li","doi":"10.1109/JMMCT.2023.3311322","DOIUrl":"https://doi.org/10.1109/JMMCT.2023.3311322","url":null,"abstract":"This article presents a computationally efficient framework for identifying resonance modes of 3D radio-frequency (RF) cavities with damping waveguide ports. The proposed framework relies on surface integral equation (IE) formulations to convert the task of resonance detection to the task of finding frequencies at which the lowest few eigenvalues of the system matrix is close to zero. For the linear eigenvalue problem with a fixed frequency, we propose leveraging fast direct solvers to efficiently invert the system matrix; for the frequency search problem, we develop a hybrid optimization algorithm that combines Bayesian optimization with down-hill simplex optimization. The proposed IE-based resonance detection framework (IERD) has been applied to detection of high-order resonance modes (HOMs) of realistic accelerator RF cavities to demonstrate its efficiency and accuracy.","PeriodicalId":52176,"journal":{"name":"IEEE Journal on Multiscale and Multiphysics Computational Techniques","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-09-04","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49962813","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-24DOI: 10.1109/JMMCT.2023.3307180
Viswarupa V;Yoginder Kumar Negi;N. Balakrishnan
In this article, we show the RCS enhancement due to the acoustic disturbances around a pulsating sphere. The acoustic variation is modelled with the dielectric inhomogeneities around the sphere caused by the pressure fluctuations due to the acoustic source. RCS is computed for the modelled dielectric pulsating sphere, a cube, and a cone on a cylinder across a frequency band using Finite Difference Time Domain (FDTD) method. The RCS of the pulsating sphere and other objects considered are dominated by the background scattering from the pulsating object. In this work, we show that the dielectric variation due to the acoustic source can be detected even if there is no scattering from the object. The scattering from the dielectric variation leads to the detection of Bragg scattering along with a significant increase in RCS.
{"title":"Electro-Acoustic Scattering From a Pulsating Sphere","authors":"Viswarupa V;Yoginder Kumar Negi;N. Balakrishnan","doi":"10.1109/JMMCT.2023.3307180","DOIUrl":"https://doi.org/10.1109/JMMCT.2023.3307180","url":null,"abstract":"In this article, we show the RCS enhancement due to the acoustic disturbances around a pulsating sphere. The acoustic variation is modelled with the dielectric inhomogeneities around the sphere caused by the pressure fluctuations due to the acoustic source. RCS is computed for the modelled dielectric pulsating sphere, a cube, and a cone on a cylinder across a frequency band using Finite Difference Time Domain (FDTD) method. The RCS of the pulsating sphere and other objects considered are dominated by the background scattering from the pulsating object. In this work, we show that the dielectric variation due to the acoustic source can be detected even if there is no scattering from the object. The scattering from the dielectric variation leads to the detection of Bragg scattering along with a significant increase in RCS.","PeriodicalId":52176,"journal":{"name":"IEEE Journal on Multiscale and Multiphysics Computational Techniques","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-08-24","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49962812","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-17DOI: 10.1109/JMMCT.2023.3306154
Christian Rümpler;Albert Zacharias;Rakesh B. Chechare;Li Yu;Carsten Dehning
Electric arc discharges in low–voltage (LV) or medium–voltage (MV) power distribution devices can cause significant pressure rise. For example, a high amplitude pressure peak can damage the housing of a LV circuit breaker initiating cracks during short circuit interruption. In case of larger deformations or creation of additional gaps, the impact of the geometric changes on the pressure rise cannot be neglected. This article describes a new three–codes–coupling approach, wherein a magneto–hydrodynamics (MHD) model consisting of a fluid–flow solver and an electromagnetic solver are coupled with a structural dynamics solver to build a complex co–simulation model. This model can predict the deformation of structures under the influence of arcing pressure. The applicability of the model was tested with a setup, where an electric arc is ignited inside an arc chamber that has a flexible plate on one side. Predicted pressure rise and displacement results are in good agreement with test data. In a more complex setup, this approach was applied to model the bending of a flexible baffle plate in the venting path of a LV circuit breaker during short circuit interruption. Additional challenges such as contact motion and pre–stress analysis were resolved.
{"title":"Coupling of Magneto–Hydrodynamics and Structural Models to Predict Wall Deformation due to Arcing","authors":"Christian Rümpler;Albert Zacharias;Rakesh B. Chechare;Li Yu;Carsten Dehning","doi":"10.1109/JMMCT.2023.3306154","DOIUrl":"https://doi.org/10.1109/JMMCT.2023.3306154","url":null,"abstract":"Electric arc discharges in low–voltage (LV) or medium–voltage (MV) power distribution devices can cause significant pressure rise. For example, a high amplitude pressure peak can damage the housing of a LV circuit breaker initiating cracks during short circuit interruption. In case of larger deformations or creation of additional gaps, the impact of the geometric changes on the pressure rise cannot be neglected. This article describes a new three–codes–coupling approach, wherein a magneto–hydrodynamics (MHD) model consisting of a fluid–flow solver and an electromagnetic solver are coupled with a structural dynamics solver to build a complex co–simulation model. This model can predict the deformation of structures under the influence of arcing pressure. The applicability of the model was tested with a setup, where an electric arc is ignited inside an arc chamber that has a flexible plate on one side. Predicted pressure rise and displacement results are in good agreement with test data. In a more complex setup, this approach was applied to model the bending of a flexible baffle plate in the venting path of a LV circuit breaker during short circuit interruption. Additional challenges such as contact motion and pre–stress analysis were resolved.","PeriodicalId":52176,"journal":{"name":"IEEE Journal on Multiscale and Multiphysics Computational Techniques","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-08-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49962811","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-17DOI: 10.1109/JMMCT.2023.3305008
Jie Zhu;Thomas E. Roth;Dong-Yeop Na;Weng Cho Chew
Potential-based formulation with generalized Lorenz gauge can be used in the quantization of electromagnetic fields in inhomogeneous media. However, one often faces the redundancy of modes when finding eigenmodes from potential-based formulation. In free space, this can be explained by the connection to the well-known Helmholtz decomposition. In this work, we generalize the Helmholtz decomposition to its generalized form, echoing the use of generalized Lorenz gauge in inhomogeneous media. We formulate electromagnetics eigenvalue problems using vector potential formulation which is often used in numerical quantization. The properties of the differential operators are mathematically analyzed. Orthogonality relations between the two classes of modes are proved in both continuous and discrete space. Completeness of two sets of modes and the orthogonality relations are numerically validated in inhomogeneous anisotropic media. This work serves as a foundation for numerical quantization of electromagnetic fields in inhomogeneous media with potential-based formulation.
{"title":"Generalized Helmholtz Decomposition for Modal Analysis of Electromagnetic Problems in Inhomogeneous Media","authors":"Jie Zhu;Thomas E. Roth;Dong-Yeop Na;Weng Cho Chew","doi":"10.1109/JMMCT.2023.3305008","DOIUrl":"https://doi.org/10.1109/JMMCT.2023.3305008","url":null,"abstract":"Potential-based formulation with generalized Lorenz gauge can be used in the quantization of electromagnetic fields in inhomogeneous media. However, one often faces the redundancy of modes when finding eigenmodes from potential-based formulation. In free space, this can be explained by the connection to the well-known Helmholtz decomposition. In this work, we generalize the Helmholtz decomposition to its generalized form, echoing the use of generalized Lorenz gauge in inhomogeneous media. We formulate electromagnetics eigenvalue problems using vector potential formulation which is often used in numerical quantization. The properties of the differential operators are mathematically analyzed. Orthogonality relations between the two classes of modes are proved in both continuous and discrete space. Completeness of two sets of modes and the orthogonality relations are numerically validated in inhomogeneous anisotropic media. This work serves as a foundation for numerical quantization of electromagnetic fields in inhomogeneous media with potential-based formulation.","PeriodicalId":52176,"journal":{"name":"IEEE Journal on Multiscale and Multiphysics Computational Techniques","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-08-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49962810","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Determining the design variables of the magnetron sub-assemblies using empirical equations is a challenge. In this article, with the help of the popular backtracking search algorithm (BSA), the bare anode block of the magnetron and pill-box RF window are designed at frequency of 2.998 GHz. The convergence results with BSA are validated with the harmony search algorithm (HSA) and particle swarm optimization (PSO). The optimized design variables of bare anode are hole radius ( $a$ ), slot length ( $l_{s}$ ), slot width ( $W_{s}$ ), and anode height ( $h_{a}$ ) which are found to be 3.1, 2.9, 12.8, and 100 mm, respectively, and converge within 150 iterations with BSA. The optimized results are compared to simulated results which are nearly identical with a negligible relative difference of $pi$ -mode is 1.08%. From the pill-box RF window design, multi-objective optimization is carried out to reach the desired frequency and to achieve minimized reflections by maximizing the bandwidth. The corresponding design variables dielectric thickness ( $t_{w}$ ), cavity length ( $C_{l}$ ), and cavity radius ( $C_{r}$ ) which are 2.5, 30.4, and 41.5 mm, respectively. Pareto multi-objective BSA (PMBSA) is validated with the weighted sum approach (WSA). Due to its simplicity and lower latency, optimization approach is helpful to designers to develop the microwave devices.
{"title":"Optimization Using Backtracking Search Algorithm for the Design of Magnetron Anode Block and Pill-Box RF Window","authors":"Patibandla Anilkumar;Dobbidi Pamu;Tapeshwar Tiwari","doi":"10.1109/JMMCT.2023.3304970","DOIUrl":"https://doi.org/10.1109/JMMCT.2023.3304970","url":null,"abstract":"Determining the design variables of the magnetron sub-assemblies using empirical equations is a challenge. In this article, with the help of the popular backtracking search algorithm (BSA), the bare anode block of the magnetron and pill-box RF window are designed at frequency of 2.998 GHz. The convergence results with BSA are validated with the harmony search algorithm (HSA) and particle swarm optimization (PSO). The optimized design variables of bare anode are hole radius (\u0000<inline-formula><tex-math>$a$</tex-math></inline-formula>\u0000), slot length (\u0000<inline-formula><tex-math>$l_{s}$</tex-math></inline-formula>\u0000), slot width (\u0000<inline-formula><tex-math>$W_{s}$</tex-math></inline-formula>\u0000), and anode height (\u0000<inline-formula><tex-math>$h_{a}$</tex-math></inline-formula>\u0000) which are found to be 3.1, 2.9, 12.8, and 100 mm, respectively, and converge within 150 iterations with BSA. The optimized results are compared to simulated results which are nearly identical with a negligible relative difference of \u0000<inline-formula><tex-math>$pi$</tex-math></inline-formula>\u0000-mode is 1.08%. From the pill-box RF window design, multi-objective optimization is carried out to reach the desired frequency and to achieve minimized reflections by maximizing the bandwidth. The corresponding design variables dielectric thickness (\u0000<inline-formula><tex-math>$t_{w}$</tex-math></inline-formula>\u0000), cavity length (\u0000<inline-formula><tex-math>$C_{l}$</tex-math></inline-formula>\u0000), and cavity radius (\u0000<inline-formula><tex-math>$C_{r}$</tex-math></inline-formula>\u0000) which are 2.5, 30.4, and 41.5 mm, respectively. Pareto multi-objective BSA (PMBSA) is validated with the weighted sum approach (WSA). Due to its simplicity and lower latency, optimization approach is helpful to designers to develop the microwave devices.","PeriodicalId":52176,"journal":{"name":"IEEE Journal on Multiscale and Multiphysics Computational Techniques","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49962808","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-14DOI: 10.1109/JMMCT.2023.3304709
Sami Barmada;Paolo Di Barba;Nunzia Fontana;Maria Evelina Mognaschi;Mauro Tucci
In this work, a Deep Learning approach based on a Conditional Variational Autoencoder (CVAE) and a Convolutional Neural Network (CNN) has been adopted for the solution of inverse problems and electromagnetic field reconstruction; the method is applied to the TEAM 35 benchmark magnetostatic problem. The aim of the proposed method is twofold: first, knowing the magnetic field distribution in a subdomain, the magnetic field distribution ${bm{B}}$ in the whole domain is determined (field reconstruction problem). For this problem a CVAE is proposed and trained. The CVAE prediction is based on an optimization procedure in the latent space, which uses an automatic differentiation technique. Subsequently, knowing the magnetic field distribution in the whole domain, the aim is to find, using a CNN regression model, the geometrical characteristics of the source (source identification problem).
{"title":"Electromagnetic Field Reconstruction and Source Identification Using Conditional Variational Autoencoder and CNN","authors":"Sami Barmada;Paolo Di Barba;Nunzia Fontana;Maria Evelina Mognaschi;Mauro Tucci","doi":"10.1109/JMMCT.2023.3304709","DOIUrl":"https://doi.org/10.1109/JMMCT.2023.3304709","url":null,"abstract":"In this work, a Deep Learning approach based on a Conditional Variational Autoencoder (CVAE) and a Convolutional Neural Network (CNN) has been adopted for the solution of inverse problems and electromagnetic field reconstruction; the method is applied to the TEAM 35 benchmark magnetostatic problem. The aim of the proposed method is twofold: first, knowing the magnetic field distribution in a subdomain, the magnetic field distribution \u0000<inline-formula><tex-math>${bm{B}}$</tex-math></inline-formula>\u0000 in the whole domain is determined (field reconstruction problem). For this problem a CVAE is proposed and trained. The CVAE prediction is based on an optimization procedure in the latent space, which uses an automatic differentiation technique. Subsequently, knowing the magnetic field distribution in the whole domain, the aim is to find, using a CNN regression model, the geometrical characteristics of the source (source identification problem).","PeriodicalId":52176,"journal":{"name":"IEEE Journal on Multiscale and Multiphysics Computational Techniques","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-08-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49962809","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
Pub Date : 2023-08-09DOI: 10.1109/JMMCT.2023.3303813
Arman Afsari;Paulo de Souza;Amin Abbosh;Yahya Rahmat-Samii
Laws of physics remain unchanged under translational motion of coordinates. To guarantee the above postulate in electromagnetics, Lorenz gauge eliminates the additional terms generated in the wave equation of magnetic vector potential during translational motion. When it comes to computational electromagnetics, nonetheless, Coulomb gauge is still preferred to represent the divergence of the magnetic vector potential; the vector basis functions involved in the computation of magnetic vector potential are thus divergence-free. There is, however, an immediate consequence that we shall consider here. These vector basis functions cannot incorporate any kinematic transformation of the system of coordinates. The solution achieved by them is, therefore, invalid under translational motion of the system of coordinates as a whole. Less attention has been paid to this side of computational electromagnetics, as the problems that we solve do not usually undergo any kinematic transformation. The new meshless vector basis function presented in this article is Lorentz-invariant. The solution achieved by it is, therefore, valid under translational motion. Even in local problems, the solution achieved by the newly-introduced Lorentz-invariant vector basis function demonstrates more accuracy and efficiency with respect to the solution achieved by the divergence-free vector basis functions in meshless method.
{"title":"Lorentz-Invariant Meshless Vector Basis Function for Translational Motion of Coordinates in Computational Electromagnetics","authors":"Arman Afsari;Paulo de Souza;Amin Abbosh;Yahya Rahmat-Samii","doi":"10.1109/JMMCT.2023.3303813","DOIUrl":"https://doi.org/10.1109/JMMCT.2023.3303813","url":null,"abstract":"Laws of physics remain unchanged under translational motion of coordinates. To guarantee the above postulate in electromagnetics, Lorenz gauge eliminates the additional terms generated in the wave equation of magnetic vector potential during translational motion. When it comes to computational electromagnetics, nonetheless, Coulomb gauge is still preferred to represent the divergence of the magnetic vector potential; the vector basis functions involved in the computation of magnetic vector potential are thus divergence-free. There is, however, an immediate consequence that we shall consider here. These vector basis functions cannot incorporate any kinematic transformation of the system of coordinates. The solution achieved by them is, therefore, invalid under translational motion of the system of coordinates as a whole. Less attention has been paid to this side of computational electromagnetics, as the problems that we solve do not usually undergo any kinematic transformation. The new meshless vector basis function presented in this article is Lorentz-invariant. The solution achieved by it is, therefore, valid under translational motion. Even in local problems, the solution achieved by the newly-introduced Lorentz-invariant vector basis function demonstrates more accuracy and efficiency with respect to the solution achieved by the divergence-free vector basis functions in meshless method.","PeriodicalId":52176,"journal":{"name":"IEEE Journal on Multiscale and Multiphysics Computational Techniques","volume":null,"pages":null},"PeriodicalIF":2.3,"publicationDate":"2023-08-09","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49962914","PeriodicalName":null,"FirstCategoryId":null,"ListUrlMain":null,"RegionNum":0,"RegionCategory":"","ArticlePicture":[],"TitleCN":null,"AbstractTextCN":null,"PMCID":"","EPubDate":null,"PubModel":null,"JCR":null,"JCRName":null,"Score":null,"Total":0}
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