Pub Date : 2014-05-14DOI: 10.1109/NEMO.2014.6995658
A. Leggieri, D. Passi, F. Di Paolo
This paper proposes a particular design technique of an 8 slots resonant cavities X-Band Magnetron. Such study is based on a Multiphysics (MP) simulation and consider thermal-structural effects due to the cathode heating, taking into account that electromagnetic behavior and thus device efficiency depend critically to the operating temperature and to the related thermal induced displacements of the materials. The proposed study involves Thermal Stress (TS), Eigen-frequency (EF) and Particle Tracing (PT) analysis performed with the Finite Element Method (FEM). These computations have been performed on COMSOL. Electric field related to the main resonant modes and particle trajectories have been computed in thermo mechanical operative conditions. Magnetron working points have been estimated.
{"title":"Multiphysics modeling based design of a key-holes magnetron","authors":"A. Leggieri, D. Passi, F. Di Paolo","doi":"10.1109/NEMO.2014.6995658","DOIUrl":"https://doi.org/10.1109/NEMO.2014.6995658","url":null,"abstract":"This paper proposes a particular design technique of an 8 slots resonant cavities X-Band Magnetron. Such study is based on a Multiphysics (MP) simulation and consider thermal-structural effects due to the cathode heating, taking into account that electromagnetic behavior and thus device efficiency depend critically to the operating temperature and to the related thermal induced displacements of the materials. The proposed study involves Thermal Stress (TS), Eigen-frequency (EF) and Particle Tracing (PT) analysis performed with the Finite Element Method (FEM). These computations have been performed on COMSOL. Electric field related to the main resonant modes and particle trajectories have been computed in thermo mechanical operative conditions. Magnetron working points have been estimated.","PeriodicalId":273349,"journal":{"name":"2014 International Conference on Numerical Electromagnetic Modeling and Optimization for RF, Microwave, and Terahertz Applications (NEMO)","volume":"61 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"126547940","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 : 2014-05-14DOI: 10.1109/NEMO.2014.6995722
P. Gamba
In this paper, one of the peculiar applications of the Boundary Integral - Resonant Mode Expansion (BI-RME) method, namely shape analysis and recognition, is reviewed. We explore the advantages for shape analysis and recognition of a BI-RME based modal matching algorithm, where each shape is represented by means of a set of eigenfunctions, solutions of the Helmotz equation with Dirichlet boundary condition. These solutions correspond to the vibration modes of an elastic sheet when its boundary is considered as fixed.
{"title":"BI-RME as a pattern recognition tool","authors":"P. Gamba","doi":"10.1109/NEMO.2014.6995722","DOIUrl":"https://doi.org/10.1109/NEMO.2014.6995722","url":null,"abstract":"In this paper, one of the peculiar applications of the Boundary Integral - Resonant Mode Expansion (BI-RME) method, namely shape analysis and recognition, is reviewed. We explore the advantages for shape analysis and recognition of a BI-RME based modal matching algorithm, where each shape is represented by means of a set of eigenfunctions, solutions of the Helmotz equation with Dirichlet boundary condition. These solutions correspond to the vibration modes of an elastic sheet when its boundary is considered as fixed.","PeriodicalId":273349,"journal":{"name":"2014 International Conference on Numerical Electromagnetic Modeling and Optimization for RF, Microwave, and Terahertz Applications (NEMO)","volume":"49 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"132016765","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 : 2014-05-14DOI: 10.1109/NEMO.2014.6995669
P. So, W. Hoefer
A fundamental rule in Transmission Line Matrix (TLM) modeling is to ensure that the shortest wavelength in the model is always large compared to the discretization parameter. This rule is appropriate for electromagnetic analysis, but when the TLM model is used to solve inverse problems, such as computational imaging, source reconstruction, or structure synthesis - procedures that involve computational reversal of time - this wavelength restriction severely compromises the spatial resolution of the procedure by virtue of the Abbe limit. By discarding this rule we achieve super-resolution in source reconstruction using time reversal. We leverage the Johns Matrix concept and the reciprocity of TLM to achieve a breakthrough where previous attempts at structure synthesis through time reversal have been unsatisfactory.
{"title":"A new look at computational time reversal in TLM","authors":"P. So, W. Hoefer","doi":"10.1109/NEMO.2014.6995669","DOIUrl":"https://doi.org/10.1109/NEMO.2014.6995669","url":null,"abstract":"A fundamental rule in Transmission Line Matrix (TLM) modeling is to ensure that the shortest wavelength in the model is always large compared to the discretization parameter. This rule is appropriate for electromagnetic analysis, but when the TLM model is used to solve inverse problems, such as computational imaging, source reconstruction, or structure synthesis - procedures that involve computational reversal of time - this wavelength restriction severely compromises the spatial resolution of the procedure by virtue of the Abbe limit. By discarding this rule we achieve super-resolution in source reconstruction using time reversal. We leverage the Johns Matrix concept and the reciprocity of TLM to achieve a breakthrough where previous attempts at structure synthesis through time reversal have been unsatisfactory.","PeriodicalId":273349,"journal":{"name":"2014 International Conference on Numerical Electromagnetic Modeling and Optimization for RF, Microwave, and Terahertz Applications (NEMO)","volume":"13 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"117126707","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 : 2014-05-14DOI: 10.1109/NEMO.2014.6995701
S. Bellucci, S. Bistarelli, A. Cataldo, F. Micciulla, J. Macutkevič, I. Kranauskaitė, J. Banys, P. Kuzhir, N. Volynets, A. Paddubskaya, D. Bychanok, S. Maksimenko, V. Fierro, A. Celzard
Composite materials based on epoxy resin filled with various kinds of graphite particles: exfoliated graphite (EG), natural graphite, and coarse, medium and fine artificial graphites have been prepared. The dielectric permittivity strongly increases with graphite particle size. This effect is related to the distance of the investigated filler concentrations to the composites' percolation threshold. Microwave experiments show that exfoliated graphite is, out of investigated graphite particles, the only one being a really effective additive for producing electromagnetic (EM) interference (EMI) shielding: 2 wt.% epoxy/EG is absolutely opaque to electromagnetic radiation at 30 GHz.
{"title":"Microwave response properties of epoxy resin composites filled with graphitic fillers","authors":"S. Bellucci, S. Bistarelli, A. Cataldo, F. Micciulla, J. Macutkevič, I. Kranauskaitė, J. Banys, P. Kuzhir, N. Volynets, A. Paddubskaya, D. Bychanok, S. Maksimenko, V. Fierro, A. Celzard","doi":"10.1109/NEMO.2014.6995701","DOIUrl":"https://doi.org/10.1109/NEMO.2014.6995701","url":null,"abstract":"Composite materials based on epoxy resin filled with various kinds of graphite particles: exfoliated graphite (EG), natural graphite, and coarse, medium and fine artificial graphites have been prepared. The dielectric permittivity strongly increases with graphite particle size. This effect is related to the distance of the investigated filler concentrations to the composites' percolation threshold. Microwave experiments show that exfoliated graphite is, out of investigated graphite particles, the only one being a really effective additive for producing electromagnetic (EM) interference (EMI) shielding: 2 wt.% epoxy/EG is absolutely opaque to electromagnetic radiation at 30 GHz.","PeriodicalId":273349,"journal":{"name":"2014 International Conference on Numerical Electromagnetic Modeling and Optimization for RF, Microwave, and Terahertz Applications (NEMO)","volume":"25 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114939374","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 : 2014-05-14DOI: 10.1109/NEMO.2014.6995653
P. Arcioni, M. Bozzi, M. Bressan, G. Conciauro, L. Perregrini
This paper will provide an historical overview of the development of the BI-RME method. The original idea behind the BI-RME method - dating back to late seventies - will be briefly described, and its application to the development of specific algorithms and computer codes for the analysis and design of several classes of components and circuits will be reported.
{"title":"The BI-RME method: An historical overview","authors":"P. Arcioni, M. Bozzi, M. Bressan, G. Conciauro, L. Perregrini","doi":"10.1109/NEMO.2014.6995653","DOIUrl":"https://doi.org/10.1109/NEMO.2014.6995653","url":null,"abstract":"This paper will provide an historical overview of the development of the BI-RME method. The original idea behind the BI-RME method - dating back to late seventies - will be briefly described, and its application to the development of specific algorithms and computer codes for the analysis and design of several classes of components and circuits will be reported.","PeriodicalId":273349,"journal":{"name":"2014 International Conference on Numerical Electromagnetic Modeling and Optimization for RF, Microwave, and Terahertz Applications (NEMO)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128669154","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 : 2014-05-14DOI: 10.1109/NEMO.2014.6995698
M. Dionigi, M. Mongiardo
A numerical electromagnetic modeling of a Wireless power system is presented. The system is composed of spiral resonators and loop inductances coupled by their magnetic and electric fields. Based on the full-wave simulation a network model of the system is derived allowing one to have a deeper insight of the electromagnetic field surrounding the system and of their coupling properties.
{"title":"Numerical electromagnetic modeling of a wireless power transfer system","authors":"M. Dionigi, M. Mongiardo","doi":"10.1109/NEMO.2014.6995698","DOIUrl":"https://doi.org/10.1109/NEMO.2014.6995698","url":null,"abstract":"A numerical electromagnetic modeling of a Wireless power system is presented. The system is composed of spiral resonators and loop inductances coupled by their magnetic and electric fields. Based on the full-wave simulation a network model of the system is derived allowing one to have a deeper insight of the electromagnetic field surrounding the system and of their coupling properties.","PeriodicalId":273349,"journal":{"name":"2014 International Conference on Numerical Electromagnetic Modeling and Optimization for RF, Microwave, and Terahertz Applications (NEMO)","volume":"277 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"114141319","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 : 2014-05-14DOI: 10.1109/NEMO.2014.6995704
M. A. Fiaz, C. Ponti, G. Schettini
Cylindrical Wave Approach is applied to the scattering by a cylinder placed below a rough surface, and combined to Small Perturbation Method in the first-order approximation. In the theoretical approach, a surface with arbitrary profile is dealt with. As to the numerical solution, two alternative implementations of the surface are proposed: a sinusoidal profile and a periodic surface with samples from a Gaussian roughness spectrum. The developed method can be applied to the simulation of scattering by buried objects in a realistic environment with natural unevenesses.
{"title":"On the scattering by a cylindrical object below a rough surface with the CWA","authors":"M. A. Fiaz, C. Ponti, G. Schettini","doi":"10.1109/NEMO.2014.6995704","DOIUrl":"https://doi.org/10.1109/NEMO.2014.6995704","url":null,"abstract":"Cylindrical Wave Approach is applied to the scattering by a cylinder placed below a rough surface, and combined to Small Perturbation Method in the first-order approximation. In the theoretical approach, a surface with arbitrary profile is dealt with. As to the numerical solution, two alternative implementations of the surface are proposed: a sinusoidal profile and a periodic surface with samples from a Gaussian roughness spectrum. The developed method can be applied to the simulation of scattering by buried objects in a realistic environment with natural unevenesses.","PeriodicalId":273349,"journal":{"name":"2014 International Conference on Numerical Electromagnetic Modeling and Optimization for RF, Microwave, and Terahertz Applications (NEMO)","volume":"1 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"128053736","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 : 2014-05-14DOI: 10.1109/NEMO.2014.6995683
G. Selcuk, S. Koc
Solving electric field integral equation (EFIE) with Nyström method requires accurate evaluation of hypersingular surface integrals since this method does not use divergence conforming basis and testing functions. The success of the method also depends on accurate representation of non-planar characteristics of the scattering object. In this study Hadamard finite part interpretation is used to evaluate hypersingular integrals over non-planar surfaces, which are represented by their Taylor series expansions. Numerical tests are conducted to show the effectiveness of the formulas. Also a scattering problem is solved which confirms the accuracy.
{"title":"Evaluation of hypersingular integrals on non-planar surfaces","authors":"G. Selcuk, S. Koc","doi":"10.1109/NEMO.2014.6995683","DOIUrl":"https://doi.org/10.1109/NEMO.2014.6995683","url":null,"abstract":"Solving electric field integral equation (EFIE) with Nyström method requires accurate evaluation of hypersingular surface integrals since this method does not use divergence conforming basis and testing functions. The success of the method also depends on accurate representation of non-planar characteristics of the scattering object. In this study Hadamard finite part interpretation is used to evaluate hypersingular integrals over non-planar surfaces, which are represented by their Taylor series expansions. Numerical tests are conducted to show the effectiveness of the formulas. Also a scattering problem is solved which confirms the accuracy.","PeriodicalId":273349,"journal":{"name":"2014 International Conference on Numerical Electromagnetic Modeling and Optimization for RF, Microwave, and Terahertz Applications (NEMO)","volume":"21 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133059993","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 : 2014-05-14DOI: 10.1109/NEMO.2014.6995665
F. Feng, Chao Zhang, Venu-Madhav-Reddy Gongal-Reddy, Qi-jun Zhang
Space mapping is an effective method for speeding up EM optimization. The method normally requires an equivalent circuit as the coarse model. This paper addresses the situation when an equivalent circuit coarse model is not available. We establish our coarse model using a lookup table to store the data of coarse mesh EM simulations and its derivatives, avoiding the EM re-simulations w.r.t. the same values of design variables. In the proposed method, the surrogate model is developed using knowledge-based neural network (KBNN) combining the coarse model with a neural network. Our technique uses mostly coarse mesh EM evaluation and occasionally fine mesh EM evaluation to achieve optimal EM solutions with fine mesh accuracy. This technique is illustrated by two microwave filter examples.
{"title":"Knowledge-based coarse and fine mesh space mapping approach to EM optimization","authors":"F. Feng, Chao Zhang, Venu-Madhav-Reddy Gongal-Reddy, Qi-jun Zhang","doi":"10.1109/NEMO.2014.6995665","DOIUrl":"https://doi.org/10.1109/NEMO.2014.6995665","url":null,"abstract":"Space mapping is an effective method for speeding up EM optimization. The method normally requires an equivalent circuit as the coarse model. This paper addresses the situation when an equivalent circuit coarse model is not available. We establish our coarse model using a lookup table to store the data of coarse mesh EM simulations and its derivatives, avoiding the EM re-simulations w.r.t. the same values of design variables. In the proposed method, the surrogate model is developed using knowledge-based neural network (KBNN) combining the coarse model with a neural network. Our technique uses mostly coarse mesh EM evaluation and occasionally fine mesh EM evaluation to achieve optimal EM solutions with fine mesh accuracy. This technique is illustrated by two microwave filter examples.","PeriodicalId":273349,"journal":{"name":"2014 International Conference on Numerical Electromagnetic Modeling and Optimization for RF, Microwave, and Terahertz Applications (NEMO)","volume":"16 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"133397841","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 : 2014-05-14DOI: 10.1109/NEMO.2014.6995718
S. Plonnigs, W. Mathis, A. Reibiger
In this paper we consider electro-magnetic systems where model complexity can be reduced by means of network and transmission line theory. However, the modeling concepts are derived under certain conditions from Maxwell's equations. We will discuss the restrictions regarding the interconnections of networks and transmission lines that can be used for the development of models of electromagnetic systems with a reduced complexity. Furthermore, we show the relationship between the magnetic field of wires calculated by Biot-Savart's formula and transmission line theory.
{"title":"Some restrictions for the representation of electro-magnetic systems as transmission-line coupled networks","authors":"S. Plonnigs, W. Mathis, A. Reibiger","doi":"10.1109/NEMO.2014.6995718","DOIUrl":"https://doi.org/10.1109/NEMO.2014.6995718","url":null,"abstract":"In this paper we consider electro-magnetic systems where model complexity can be reduced by means of network and transmission line theory. However, the modeling concepts are derived under certain conditions from Maxwell's equations. We will discuss the restrictions regarding the interconnections of networks and transmission lines that can be used for the development of models of electromagnetic systems with a reduced complexity. Furthermore, we show the relationship between the magnetic field of wires calculated by Biot-Savart's formula and transmission line theory.","PeriodicalId":273349,"journal":{"name":"2014 International Conference on Numerical Electromagnetic Modeling and Optimization for RF, Microwave, and Terahertz Applications (NEMO)","volume":"457 1","pages":"0"},"PeriodicalIF":0.0,"publicationDate":"2014-05-14","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"123050257","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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