Deanna Sessions, K. Fuchi, Sumana Pallampati, David Grayson, Steven R. Seiler, G. Bazzan, G. Reich, P. Buskohl, G. Huff
Frequency selective surfaces (FSS) filter specific electromagnetic (EM) frequencies defined by the geometry and often fixed periodic spacing of a conductive element array. By embedding the FSS pattern into an origami structure, we expand the number of physical configurations and periodicities of the FSS, allowing for fold-driven frequency tuning. The goal of this work is to examine the folddependent polarization and frequency behavior of an origami-inspired FSS under normal incidence and provide physical insight into its performance. The FSS is tessellated with the Miura-ori pattern and uses resonant length metallic dipoles with orthogonal orientations for two primary modes of polarization. A driven dipole model with geometric morphologies, representative of the folding operations, provides physical insight into the observed behavior of the FSS. Full-wave simulations and experimental results demonstrate a shift in resonant frequency and transmissivity with folding, highlighting the potential of origami structures as an underlying mechanism to achieve fold-driven EM agility in FSSs.
{"title":"INVESTIGATION OF FOLD-DEPENDENT BEHAVIOR IN AN ORIGAMI-INSPIRED FSS UNDER NORMAL INCIDENCE","authors":"Deanna Sessions, K. Fuchi, Sumana Pallampati, David Grayson, Steven R. Seiler, G. Bazzan, G. Reich, P. Buskohl, G. Huff","doi":"10.2528/PIERM17092504","DOIUrl":"https://doi.org/10.2528/PIERM17092504","url":null,"abstract":"Frequency selective surfaces (FSS) filter specific electromagnetic (EM) frequencies defined by the geometry and often fixed periodic spacing of a conductive element array. By embedding the FSS pattern into an origami structure, we expand the number of physical configurations and periodicities of the FSS, allowing for fold-driven frequency tuning. The goal of this work is to examine the folddependent polarization and frequency behavior of an origami-inspired FSS under normal incidence and provide physical insight into its performance. The FSS is tessellated with the Miura-ori pattern and uses resonant length metallic dipoles with orthogonal orientations for two primary modes of polarization. A driven dipole model with geometric morphologies, representative of the folding operations, provides physical insight into the observed behavior of the FSS. Full-wave simulations and experimental results demonstrate a shift in resonant frequency and transmissivity with folding, highlighting the potential of origami structures as an underlying mechanism to achieve fold-driven EM agility in FSSs.","PeriodicalId":39028,"journal":{"name":"Progress in Electromagnetics Research M","volume":"63 1","pages":"131-139"},"PeriodicalIF":1.0,"publicationDate":"2018-01-11","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2528/PIERM17092504","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49258723","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}
C. Warren, S. Šesnić, A. Ventura, L. Pajewski, D. Poljak, A. Giannopoulos
In this paper we compare current implementations of commonly used numerical techniques - the Finite-Difference Time-Domain (FDTD) method, the Finite-Integration Technique (FIT), and Time-Domain Integral Equations (TDIE) - to solve the canonical problem of a horizontal dipole antenna radiating over lossless and lossy half-spaces. These types of environment are important starting points for simulating many Ground Penetrating Radar (GPR applications which operate in the near-field of the antenna, where the interaction among the antenna, the ground, and targets is important. We analysed the simulated current at the centre of the dipole antenna, as well as the electric field at different distances from the centre of the antenna inside the half-space. We observed that the results from the simulations using the FDTD and FIT methods agreed well with each other in all of the environments. Comparisons of the electric field showed that the TDIE technique agreed with the FDTD and FIT methods when observation distances were towards the far-field of the antenna but degraded closer to the antenna. These results provide evidence necessary to develop a hybridisation of current implementations of the FDTD and TDIE methods to capitalise on the strengths of each technique.
{"title":"Comparison of Time-Domain Finite-Difference, Finite-Integration, and Integral-Equation Methods for Dipole Radiation in Half-Space Environments","authors":"C. Warren, S. Šesnić, A. Ventura, L. Pajewski, D. Poljak, A. Giannopoulos","doi":"10.2528/PIERM17021602","DOIUrl":"https://doi.org/10.2528/PIERM17021602","url":null,"abstract":"In this paper we compare current implementations of commonly used numerical techniques - the Finite-Difference Time-Domain (FDTD) method, the Finite-Integration Technique (FIT), and Time-Domain Integral Equations (TDIE) - to solve the canonical problem of a horizontal dipole antenna radiating over lossless and lossy half-spaces. These types of environment are important starting points for simulating many Ground Penetrating Radar (GPR applications which operate in the near-field of the antenna, where the interaction among the antenna, the ground, and targets is important. We analysed the simulated current at the centre of the dipole antenna, as well as the electric field at different distances from the centre of the antenna inside the half-space. We observed that the results from the simulations using the FDTD and FIT methods agreed well with each other in all of the environments. Comparisons of the electric field showed that the TDIE technique agreed with the FDTD and FIT methods when observation distances were towards the far-field of the antenna but degraded closer to the antenna. These results provide evidence necessary to develop a hybridisation of current implementations of the FDTD and TDIE methods to capitalise on the strengths of each technique.","PeriodicalId":39028,"journal":{"name":"Progress in Electromagnetics Research M","volume":"57 1","pages":"175-183"},"PeriodicalIF":1.0,"publicationDate":"2017-06-18","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2528/PIERM17021602","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"49251968","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}
The first author is grateful to BAE Systems for data and financial support during formative stages of the work.
第一作者感谢BAE系统公司在工作形成阶段提供的数据和资金支持。
{"title":"Rough Surface Scattering via Two-Way Parabolic Integral Equation","authors":"M. Spivack, O. R. Spivack","doi":"10.2528/PIERM17021801","DOIUrl":"https://doi.org/10.2528/PIERM17021801","url":null,"abstract":"The first author is grateful to BAE Systems for data and financial support during formative stages of the work.","PeriodicalId":39028,"journal":{"name":"Progress in Electromagnetics Research M","volume":"56 1","pages":"81-90"},"PeriodicalIF":1.0,"publicationDate":"2017-04-23","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2528/PIERM17021801","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"47345703","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}
R. Suhairi, R. N. Firdaus, Zuki Nor Aishah, Fairul Azhar Abdul Shukor, N. Othman, Z. Ibrahim, C. Aravind
The improvement in the power density in the double stator configurations is feasible with increase in the electrical loading of the electrical machines. This type of newer configuration is finding significant applications in improvising energy generation, more commonly for renewable energy generation. Various double stator configurations with non-arc permanent magnet machines for power density are modelled and analyzed in this paper. Finite Element Method (FEM) is used to simulate for the generation capability including the electromagnetics parameters such as flux linkage and open circuit voltage. A new slotted rotor structure is evolved based on the magnetic flux flow control inside the machine. The proposed structure is then fabricated in the laboratory and tested for operating characteristics with load circuit. The proposed machine produces a maximum power of 600W at speed of 2000 rpm with 75% of maximum efficiency with the micro-hydro generation unit.
{"title":"Performance Characteristics Of Non-Arc Double Stator Permanent Magnet Generator","authors":"R. Suhairi, R. N. Firdaus, Zuki Nor Aishah, Fairul Azhar Abdul Shukor, N. Othman, Z. Ibrahim, C. Aravind","doi":"10.2528/PIERM16111503","DOIUrl":"https://doi.org/10.2528/PIERM16111503","url":null,"abstract":"The improvement in the power density in the double stator configurations is feasible with increase in the electrical loading of the electrical machines. This type of newer configuration is finding significant applications in improvising energy generation, more commonly for renewable energy generation. Various double stator configurations with non-arc permanent magnet machines for power density are modelled and analyzed in this paper. Finite Element Method (FEM) is used to simulate for the generation capability including the electromagnetics parameters such as flux linkage and open circuit voltage. A new slotted rotor structure is evolved based on the magnetic flux flow control inside the machine. The proposed structure is then fabricated in the laboratory and tested for operating \u0000characteristics with load circuit. The proposed machine produces a maximum power of 600W at speed of 2000 rpm with 75% of maximum efficiency with the micro-hydro generation unit.","PeriodicalId":39028,"journal":{"name":"Progress in Electromagnetics Research M","volume":"53 1","pages":"201-214"},"PeriodicalIF":1.0,"publicationDate":"2017-04-17","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"https://sci-hub-pdf.com/10.2528/PIERM16111503","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"48280333","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}
L. Warne, Yau T. Lin, K. Merewether, Kenneth C. Chen
Linear lightning diffusion into a Faraday cage is studied. An early-time integral valid for large ratios of enclosure size to enclosure thickness and small relative permeability ({mu}/{mu}{sub 0} {le} 10) is used for this study. Existing solutions for nearby lightning impulse responses of electrically thick-wall enclosures are refined and extended to calculate the nearby lightning magnetic field (H) and time-derivative magnetic field (HDOT) inside enclosures of varying thickness caused by a decaying exponential excitation. For a direct strike scenario, the early-time integral for a worst-case line source outside the enclosure caused by an impulse is simplified and numerically integrated to give the interior H and HDOT at the location closest to the source as well as a function of distance from the source. H and HDOT enclosure response functions for decaying exponentials are considered for an enclosure wall of any thickness. Simple formulas are derived to provide a description of enclosure interior H and HDOT as well. Direct strike voltage and current bounds for a single-turn optimally-coupled loop for all three waveforms are also given.
{"title":"Linear Diffusion into a Faraday Cage","authors":"L. Warne, Yau T. Lin, K. Merewether, Kenneth C. Chen","doi":"10.2172/1031311","DOIUrl":"https://doi.org/10.2172/1031311","url":null,"abstract":"Linear lightning diffusion into a Faraday cage is studied. An early-time integral valid for large ratios of enclosure size to enclosure thickness and small relative permeability ({mu}/{mu}{sub 0} {le} 10) is used for this study. Existing solutions for nearby lightning impulse responses of electrically thick-wall enclosures are refined and extended to calculate the nearby lightning magnetic field (H) and time-derivative magnetic field (HDOT) inside enclosures of varying thickness caused by a decaying exponential excitation. For a direct strike scenario, the early-time integral for a worst-case line source outside the enclosure caused by an impulse is simplified and numerically integrated to give the interior H and HDOT at the location closest to the source as well as a function of distance from the source. H and HDOT enclosure response functions for decaying exponentials are considered for an enclosure wall of any thickness. Simple formulas are derived to provide a description of enclosure interior H and HDOT as well. Direct strike voltage and current bounds for a single-turn optimally-coupled loop for all three waveforms are also given.","PeriodicalId":39028,"journal":{"name":"Progress in Electromagnetics Research M","volume":"23 1","pages":"299-311"},"PeriodicalIF":1.0,"publicationDate":"2012-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"68213753","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}
Z. E. Elshaikh, M. R. Islam, Othman Omran Khalifa, H. E. Abdel-Raouf
The microwave signal attenuation caused by dust is one of the major problems in utilizing microwave bands for terrestrial and space communication especially at desert and semi desert area. This paper presents a mathematical model developed to characterize the microwave signal attenuation due to dust. This model enables a convenient calculation of the microwave signal path attenuation which relates attenuation to visibility, frequency, particle size and complex permittivity. The predicted values from the mathematical model, which are compared with the measured values observed by the author in Sudan show relatively optimistic agreement.
{"title":"MATHEMATICAL MODEL FOR THE PREDICTION OF MICROWAVE SIGNAL ATTENUATION DUE TO DUSTSTORM","authors":"Z. E. Elshaikh, M. R. Islam, Othman Omran Khalifa, H. E. Abdel-Raouf","doi":"10.2528/PIERM09021906","DOIUrl":"https://doi.org/10.2528/PIERM09021906","url":null,"abstract":"The microwave signal attenuation caused by dust is one of the major problems in utilizing microwave bands for terrestrial and space communication especially at desert and semi desert area. This paper presents a mathematical model developed to characterize the microwave signal attenuation due to dust. This model enables a convenient calculation of the microwave signal path attenuation which relates attenuation to visibility, frequency, particle size and complex permittivity. The predicted values from the mathematical model, which are compared with the measured values observed by the author in Sudan show relatively optimistic agreement.","PeriodicalId":39028,"journal":{"name":"Progress in Electromagnetics Research M","volume":"41 1","pages":"139-153"},"PeriodicalIF":1.0,"publicationDate":"2009-01-01","publicationTypes":"Journal Article","fieldsOfStudy":null,"isOpenAccess":false,"openAccessPdf":"","citationCount":null,"resultStr":null,"platform":"Semanticscholar","paperid":"73478024","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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