Relevant bibliographies by topics / Electromagnetic Periodic Structures

Academic literature on the topic 'Electromagnetic Periodic Structures'

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Published: 6 September 2023

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Journal articles on the topic "Electromagnetic Periodic Structures"

1

Schmidt, G. "Electromagnetic Scattering by Periodic Structures." Journal of Mathematical Sciences 124, no. 6 (December 2004): 5390–406. http://dx.doi.org/10.1023/b:joth.0000047360.15053.7d.

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Silin, R. A. "Electromagnetic waves in artificial periodic structures." Uspekhi Fizicheskih Nauk 176, no. 5 (2006): 562. http://dx.doi.org/10.3367/ufnr.0176.200605j.0562.

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Kriegsmann, G. A. "Electromagnetic propagation in periodic porous structures." Wave Motion 36, no. 4 (October 2002): 457–72. http://dx.doi.org/10.1016/s0165-2125(02)00036-7.

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Guenneau, S., C. Geuzaine, A. Nicolet, A. B. Movchan, and F. Zolla. "Low frequency electromagnetic waves in periodic structures." International Journal of Applied Electromagnetics and Mechanics 19, no. 1-4 (April 24, 2004): 479–83. http://dx.doi.org/10.3233/jae-2004-612.

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Salary, Mohammad Mahdi, Samad Jafar-Zanjani, and Hossein Mosallaei. "ELECTROMAGNETIC SCATTERING FROM BI-PERIODIC FABRIC STRUCTURES." Progress In Electromagnetics Research B 72 (2017): 31–47. http://dx.doi.org/10.2528/pierb16103101.

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Stefanou, N., V. Karathanos, and A. Modinos. "Scattering of electromagnetic waves by periodic structures." Journal of Physics: Condensed Matter 4, no. 36 (September 7, 1992): 7389–400. http://dx.doi.org/10.1088/0953-8984/4/36/013.

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CHAN, C. T., K. M. HO, and C. M. SOUKOULIS. "PHOTONIC GAPS IN PERIODIC DIELECTRIC STRUCTURES." Modern Physics Letters B 06, no. 03 (February 10, 1992): 139–44. http://dx.doi.org/10.1142/s021798499200017x.

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Using a plane wave expansion method, we solved the Maxwell’s equations for the propagation of electromagnetic waves inside periodic dielectric materials, and found the existence of photonic band gaps in several classes of periodic dielectric structures.
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Rumpf, Raymond C., Javier J. Pazos, Jennefir L. Digaum, and Stephen M. Kuebler. "Spatially variant periodic structures in electromagnetics." Philosophical Transactions of the Royal Society A: Mathematical, Physical and Engineering Sciences 373, no. 2049 (August 28, 2015): 20140359. http://dx.doi.org/10.1098/rsta.2014.0359.

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Spatial transforms are a popular technique for designing periodic structures that are macroscopically inhomogeneous. The structures are often required to be anisotropic, provide a magnetic response, and to have extreme values for the constitutive parameters in Maxwell's equations. Metamaterials and photonic crystals are capable of providing these, although sometimes only approximately. The problem still remains about how to generate the geometry of the final lattice when it is functionally graded, or spatially varied. This paper describes a simple numerical technique to spatially vary any periodic structure while minimizing deformations to the unit cells that would weaken or destroy the electromagnetic properties. New developments in this algorithm are disclosed that increase efficiency, improve the quality of the lattices and provide the ability to design aplanatic metasurfaces. The ability to spatially vary a lattice in this manner enables new design paradigms that are not possible using spatial transforms, three of which are discussed here. First, spatially variant self-collimating photonic crystals are shown to flow unguided waves around very tight bends using ordinary materials with low refractive index. Second, multi-mode waveguides in spatially variant band gap materials are shown to guide waves around bends without mixing power between the modes. Third, spatially variant anisotropic materials are shown to sculpt the near-field around electric components. This can be used to improve electromagnetic compatibility between components in close proximity.
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Lechleiter, Armin, and Ruming Zhang. "Non-periodic acoustic and electromagnetic, scattering from periodic structures in 3D." Computers & Mathematics with Applications 74, no. 11 (December 2017): 2723–38. http://dx.doi.org/10.1016/j.camwa.2017.08.042.

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Modinos, A., V. Yannopapas, and N. Stefanou. "Scattering of electromagnetic waves by nearly periodic structures." Physical Review B 61, no. 12 (March 15, 2000): 8099–107. http://dx.doi.org/10.1103/physrevb.61.8099.

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Dissertations / Theses on the topic "Electromagnetic Periodic Structures"

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Refig, Andre. "Computational electromagnetic analysis of periodic structures." Thesis, Imperial College London, 2009. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.520979.

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Morozov, Gregory V. "Plane electromagnetic waves in layered periodic dielectric structures." Thesis, National Library of Canada = Bibliothèque nationale du Canada, 2001. http://www.collectionscanada.ca/obj/s4/f2/dsk3/ftp05/NQ62329.pdf.

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Sudhakaran, Sunil. "Negative refraction from electromagnetic periodic structures and its applications." Thesis, Queen Mary, University of London, 2006. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.430074.

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Mias, Christos Georgiou. "Finite element modelling of the electromagnetic behaviour of spatially periodic structures." Thesis, University of Cambridge, 1995. http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.361740.

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Maier, Stefan [Verfasser]. "Guiding of electromagnetic energy in subwavelength periodic metal structures / Stefan Maier." Hamburg : Diplom.de, 2003. http://d-nb.info/1184908478/34.

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Lindberg, Martin. "Mode Matching Analysis of One-Dimensional Periodic Structures." Thesis, KTH, Elektroteknisk teori och konstruktion, 2018. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-231842.

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In this thesis, we analyze the electromagnetic wave propagation in waveguidestructuresexhibiting periodical geometry, including glide symmetry. The analysisis performed using a mode matching technique which correlates the different modecoefficients from separate but, connected regions in the structure. This technique isused to obtain the dispersion diagrams for two one-dimensional periodic structures:a glide-symmetric corrugated metasurface and a coaxial line loaded with periodicholes. The mode matching formulation is presented in Cartesian and cylindricalcoordinate system for the former and the later, respectively. The mode matchingresults are compared to simulated results obtained from the Eigenmode Solver inCST Microwave Studio and are found to agree very well.
I detta examensarbete, analyseras elektromagnetisk v°agutbredning i periodiskav°agledarstrukturer som uppvisar glid symmetri. Analysen genomf¨ordes genom enmod matchnings-teknik som korrelerar de olika mod-koefficienterna fr°an separeraderegioner i strukturen med varandra. Denna teknik anv¨ands f¨or att ta framdispersionsrelationen f¨or tv°a endimensionella periodiska strukturer: en glid symmetriskkorrugerad meta-yta och en koaxial ledare belagd med periodiskt urgr¨opdah°aligheter. Mod matchnings-formuleringen presenteras i Kartesiska och cylindriskakoordinatsystem respektive f¨or de ovan n¨amnda fallen. Mod matchnings-resultatenj¨amf¨ors med data-simulerade resultat erh°allna fr°an CST Microwave Studio och de¨overenst¨ammer v¨al med varandra.
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Gudu, Tamer. "Analysis And Design Of Microstrip Printed Structures On Electromagnetic Bandgap Substrates." Phd thesis, METU, 2008. http://etd.lib.metu.edu.tr/upload/3/12609417/index.pdf.

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In the first part of the thesis, the 2-D structures in stratified media are analyzed using an efficient MoM technique. The method is used to optimize transmitted or reflected electric fields from the 2-D structures. The genetic algorithm is used in the optimization process. In the second part a 3-D MoM technique is implemented to analyze multilayered structures with periodically implanted material blocks. Using the method, the dispersion and reflection characteristics of the structure are calculated for different configurations. The results are compared with the results found in the literature and it is seen that they are in good agreement. Asymptotic Waveform Evaluation (AWE) technique is utilized to obtain the Pade approximation of the solution in terms of frequency. The high order derivatives that are required by the AWE technique are calculated through Automatic Differentiation technique. Using the AWE method, the dispersion diagram and reflection characteristics of the periodic structures are obtained in a shorter time. The results are compared with the ones obtained through direct calculation and it is seen that they are in perfect agreement. The reflection coefficients that are obtained from the 3-D MoM procedure are used to calculate Green&rsquo
s functions that approximate electric field of an infinitesimal dipole on the periodically implanted substrate. Using the calculated Green&rsquo
s functions and the spectral domain MoM procedure, dispersion characteristics of a microstrip line on the periodically implanted substrate are obtained.
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Forslund, Ola. "Scattering and propagation of electromagnetic waves in planar and curved periodic structures - applications to plane wave filters, plane wave absorbers and impedance surfaces." Doctoral thesis, KTH, Alfvén Laboratory, 2004. http://urn.kb.se/resolve?urn=urn:nbn:se:kth:diva-3825.

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The subject of this thesis is scattering of electromagneticwaves from planar and curved periodic structures. The problemspresented are solved in the frequency domain.

Scattering from planar structures with two-dimensionalperiodic dependence of constitutive parameters is treated. Theconstitutive parameters are assumed to vary continuously orstepwise in a cross section of a periodically repeating cell.The variation along a longitudinal coordinate z is arbitrary. Ageneral skew lattice is assumed. In the numerical examples, lowloss and high loss dielectric materials are considered. Theproblem is solved by expanding the .elds and constitutiveparameters in quasi-periodic and periodic functionsrespectively, which are inserted into Maxwell’s equations.Through various inner products de.ned with respect to the cell,and elimination of the longitudinal vector components, a linearsystem of ordinary di.erential equations for the transversecomponents of the .elds is obtained. After introducing apropagator, which maps the .elds from one transverse plane toanother, the system is solved by backward integration.Conventional thin metallic FSS screens of patch or aperturetype are included by obtaining generalised transmission andre.ection matrices for these surfaces. The transmission andre.ection matrices are obtained by solving spectral domainintegral equations. Comparisons of the obtained results aremade with experimental results (in one particular case), andwith results obtained using a computer code based on afundamentally di.erent time domain approach.

Scattering from thin singly curved structures consisting ofdielectric materials periodic in one dimension is alsoconsidered. Both the thickness and the period are assumed to besmall. The .elds are expanded in an asymptotic power series inthe thickness of the structure, and a scaled wave equation issolved. A propagator mapping the tangential .elds from one sideto the other of the structure is derived. An impedance boundarycondition for the structure coated on a perfect electricconductor is obtained.

Keywords:electromagnetic scattering, periodicstructure, frequency selective structure, frequency selectivesurface, grating, coupled wave analysis, electromagneticbandgap, photonic bandgap, asymptotic boundary condition,impedance boundary condition, spectral domain method,homogenisation

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Vouvakis, Marinos N. "A Non-Conformal Domain Decomposition Method for Solving Large Electromagnetic Wave Problems." The Ohio State University, 2005. http://rave.ohiolink.edu/etdc/view?acc_num=osu1125498071.

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Polat, Ozgur Murat. "Ray Anlaysis Of Electromagnetic Scattering From Semi-infinite Array Of Dipoles In Free Space." Master's thesis, METU, 2007. http://etd.lib.metu.edu.tr/upload/2/12608347/index.pdf.

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Electromagnetic wave scattering from a semi-infinite array of dipoles in free space is described by using asymptotic high frequency methods. An electric field integral expression is obtained and solved with asymptotic high frequency methods. An asymptotic field expression is obtained for a finite ×
infinite array of dipoles in free space. The analytical closed form expression for the array guided surface wave launching coefficient is obtained via a combination of an asymptotic high frequency analysis of a related reciprocal problem and Lorentz reciprocity integral formulation for the semi-infinite planar dipole array in which modified Kirchhoff approximation is used. The accuracy and the validity of the asymptotic analytical solutions are compared with the numerical solutions available in the literature before.
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Books on the topic "Electromagnetic Periodic Structures"

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Bozzi, Maurizlo, and Luca Perregrini. Periodic structures 2006. Kerala, India: Research Signpost, 2006.

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Prosvirnin, S. L. (Sergeĭ Leonidovich), ed. Wave diffraction by periodic multilayer structures. Cottenham, UK: Cambridge Scientific Publishers, 2012.

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Potylitsyn, Alexander Petrovich. Electromagnetic Radiation of Electrons in Periodic Structures. Berlin, Heidelberg: Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-19248-7.

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service), SpringerLink (Online, ed. Electromagnetic Radiation of Electrons in Periodic Structures. Berlin, Heidelberg: Springer-Verlag Berlin Heidelberg, 2011.

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Schächter, Levi. Beam-wave interaction in periodic and quasi-periodic structures. Berlin: Springer, 1997.

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service), SpringerLink (Online, ed. Beam-Wave Interaction in Periodic and Quasi-Periodic Structures. Berlin, Heidelberg: Springer-Verlag Berlin Heidelberg, 2011.

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Hwang, Ruey-Bing. Periodic Structures. Wiley & Sons, Incorporated, John, 2012.

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Potylitsyn, Alexander. Electromagnetic Radiation of Electrons in Periodic Structures. Springer, 2011.

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Potylitsyn, Alexander. Electromagnetic Radiation of Electrons in Periodic Structures. Springer Berlin / Heidelberg, 2013.

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Hwang, Ruey-Bing. Periodic Structures: Mode-Matching Approach and Applications in Electromagnetic Engineering. Wiley & Sons, Incorporated, John, 2012.

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Book chapters on the topic "Electromagnetic Periodic Structures"

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Schächter, Levi. "Elementary Electromagnetic Phenomena." In Beam-Wave Interaction in Periodic and Quasi-Periodic Structures, 27–76. Berlin, Heidelberg: Springer Berlin Heidelberg, 1997. http://dx.doi.org/10.1007/978-3-662-03398-2_2.

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Zhang, Keqian, and Dejie Li. "Periodic Structures and the Coupling of Modes." In Electromagnetic Theory for Microwaves and Optoelectronics, 365–432. Berlin, Heidelberg: Springer Berlin Heidelberg, 1998. http://dx.doi.org/10.1007/978-3-662-03553-5_6.

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Leung, K. M. "Electromagnetic Bandgap Engineering in Three-Dimensional Periodic Dielectric Structures." In Directions in Electromagnetic Wave Modeling, 457–66. Boston, MA: Springer US, 1991. http://dx.doi.org/10.1007/978-1-4899-3677-6_46.

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Ho, K. M., C. T. Chan, and C. M. Soukoulis. "Photonic Gaps for Electromagnetic Waves in Periodic Dielectric Structures: Discovery of the Diamond Structure." In Photonic Band Gaps and Localization, 235–45. Boston, MA: Springer US, 1993. http://dx.doi.org/10.1007/978-1-4899-1606-8_18.

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Semchenko, I. V., and V. E. Kaganovich. "Selective Reflection at an Oblique Incidence of Electromagnetic Waves onto Stratified Periodic Gyrotropic Structures." In Advances in Electromagnetics of Complex Media and Metamaterials, 271–80. Dordrecht: Springer Netherlands, 2002. http://dx.doi.org/10.1007/978-94-007-1067-2_16.

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Barkeshli, Kasra, and Sina Khorasani. "Periodic Structures." In Advanced Electromagnetics and Scattering Theory, 329–35. Cham: Springer International Publishing, 2014. http://dx.doi.org/10.1007/978-3-319-11547-4_10.

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Pregla, Reinhold. "Analysis of Complex Periodic Structures." In Electromagnetics and Network Theory and their Microwave Technology Applications, 277–91. Berlin, Heidelberg: Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-18375-1_20.

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Wang, Xiande, Douglas H. Werner, Jeremiah P. Turpin, and Pingjuan L. Werner. "Efficient Hybrid Algorithms for Characterizing 3-D Doubly Periodic Structures, Finite Periodic Microstrip Patch Arrays, and Aperiodic Tilings." In Computational Electromagnetics, 445–86. New York, NY: Springer New York, 2013. http://dx.doi.org/10.1007/978-1-4614-4382-7_12.

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Aris, M. A., M. T. Ali, and N. H. Abd Rahman. "Frequency Reconfigurable Aperture-Coupled Microstrip Array Antenna Using Periodic Defected Ground Structures." In Theory and Applications of Applied Electromagnetics, 61–69. Cham: Springer International Publishing, 2016. http://dx.doi.org/10.1007/978-3-319-30117-4_6.

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Russer, Johannes A., and Andreas C. Cangellaris. "Analysis of a Time-Space Periodic Filter Structure with Tunable Band-Pass Characteristic." In Electromagnetics and Network Theory and their Microwave Technology Applications, 309–17. Berlin, Heidelberg: Springer Berlin Heidelberg, 2011. http://dx.doi.org/10.1007/978-3-642-18375-1_22.

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Conference papers on the topic "Electromagnetic Periodic Structures"

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Miyamoto, Y., Y. Nakahata, S. Kirihara, M. W. Takeda, and K. Honda. "Electromagnetic Wave Localization in 3D Dielectric Fractal Structures." In Photonic Metamaterials: From Random to Periodic. Washington, D.C.: OSA, 2006. http://dx.doi.org/10.1364/meta.2006.wa5.

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Silin, R. "Electromagnetic Waves in Artificial Periodic Structures." In 2006 16th International Crimean Microwave and Telecommunication Technology. IEEE, 2006. http://dx.doi.org/10.1109/crmico.2006.256403.

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Zhu, Jing, and Ming Zhang. "Electromagnetic Scattering Analysis of Finite Periodic Structures." In 2020 International Conference on Microwave and Millimeter Wave Technology (ICMMT). IEEE, 2020. http://dx.doi.org/10.1109/icmmt49418.2020.9386358.

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Baudrand, H., M. Titaouine, N. Raveu, and G. Fontgland. "Electromagnetic modeling of planar almost periodic structures." In 2009 SBMO/IEEE MTT-S International Microwave and Optoelectronics Conference (IMOC). IEEE, 2009. http://dx.doi.org/10.1109/imoc.2009.5427552.

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Zhang, Shengjun, Lei Mu, Chunshou Shao, Xia Ai, Weidong Wang, Song Chai, Yichun Cui, et al. "Progress and prospective of electromagnetic periodic structures." In 2021 International Applied Computational Electromagnetics Society (ACES-China) Symposium. IEEE, 2021. http://dx.doi.org/10.23919/aces-china52398.2021.9581864.

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Ozgun, Ozlem, and Mustafa Kuzuoglu. "Numerical modeling of electromagnetic scattering from periodic structures by transformation electromagnetics." In 2016 10th International Congress on Advanced Electromagnetic Materials in Microwaves and Optics (METAMATERIALS). IEEE, 2016. http://dx.doi.org/10.1109/metamaterials.2016.7746508.

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Yang, Xue-Song, Jian Wang, and Bing-Zhong Wang. "Efficient Design of Periodic Pixel Layer Electromagnetic Structures." In 2018 IEEE Asia-Pacific Conference on Antennas and Propagation (APCAP). IEEE, 2018. http://dx.doi.org/10.1109/apcap.2018.8538303.

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Rui Qiang, David Jackson, Don Wilton, Ji Chen, and Wolfgang Kainz. "Time-domain modeling techniques for periodic structures." In 2008 IEEE International Symposium on Electromagnetic Compatibility - EMC 2008. IEEE, 2008. http://dx.doi.org/10.1109/isemc.2008.4652162.

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Xiong, Zubiao, and Zhong Chen. "Homogenization modeling of periodic magnetic composite structures." In 2017 IEEE International Symposium on Electromagnetic Compatibility & Signal/Power Integrity (EMCSI). IEEE, 2017. http://dx.doi.org/10.1109/isemc.2017.8077910.

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Perel, Maria V., and Mikhail S. Sidorenko. "Directed propagation of electromagnetic waves in stratified periodic structures." In 2017 XXXIInd General Assembly and Scientific Symposium of the International Union of Radio Science (URSI GASS). IEEE, 2017. http://dx.doi.org/10.23919/ursigass.2017.8105193.

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Reports on the topic "Electromagnetic Periodic Structures"

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Johnson, William Arthur, Larry Kevin Warne, Roy Eberhardt Jorgenson, Donald R. Wilton, Lorena I. Basilio, David William Peters, and F. Capolino. Analysis of electromagnetic scattering by nearly periodic structures: an LDRD report. Office of Scientific and Technical Information (OSTI), October 2006. http://dx.doi.org/10.2172/896283.

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Peterson, A. F. An Analysis of the Spectral Iterative Technique for Electromagnetic Scattering from Individual and Periodic Structures. Fort Belvoir, VA: Defense Technical Information Center, October 1986. http://dx.doi.org/10.21236/ada220310.

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BARKHATOV, NIKOLAY, and SERGEY REVUNOV. A software-computational neural network tool for predicting the electromagnetic state of the polar magnetosphere, taking into account the process that simulates its slow loading by the kinetic energy of the solar wind. SIB-Expertise, December 2021. http://dx.doi.org/10.12731/er0519.07122021.

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The auroral activity indices AU, AL, AE, introduced into geophysics at the beginning of the space era, although they have certain drawbacks, are still widely used to monitor geomagnetic activity at high latitudes. The AU index reflects the intensity of the eastern electric jet, while the AL index is determined by the intensity of the western electric jet. There are many regression relationships linking the indices of magnetic activity with a wide range of phenomena observed in the Earth's magnetosphere and atmosphere. These relationships determine the importance of monitoring and predicting geomagnetic activity for research in various areas of solar-terrestrial physics. The most dramatic phenomena in the magnetosphere and high-latitude ionosphere occur during periods of magnetospheric substorms, a sensitive indicator of which is the time variation and value of the AL index. Currently, AL index forecasting is carried out by various methods using both dynamic systems and artificial intelligence. Forecasting is based on the close relationship between the state of the magnetosphere and the parameters of the solar wind and the interplanetary magnetic field (IMF). This application proposes an algorithm for describing the process of substorm formation using an instrument in the form of an Elman-type ANN by reconstructing the AL index using the dynamics of the new integral parameter we introduced. The use of an integral parameter at the input of the ANN makes it possible to simulate the structure and intellectual properties of the biological nervous system, since in this way an additional realization of the memory of the prehistory of the modeled process is provided.
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Galili, Naftali, Roger P. Rohrbach, Itzhak Shmulevich, Yoram Fuchs, and Giora Zauberman. Non-Destructive Quality Sensing of High-Value Agricultural Commodities Through Response Analysis. United States Department of Agriculture, October 1994. http://dx.doi.org/10.32747/1994.7570549.bard.

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The objectives of this project were to develop nondestructive methods for detection of internal properties and firmness of fruits and vegetables. One method was based on a soft piezoelectric film transducer developed in the Technion, for analysis of fruit response to low-energy excitation. The second method was a dot-matrix piezoelectric transducer of North Carolina State University, developed for contact-pressure analysis of fruit during impact. Two research teams, one in Israel and the other in North Carolina, coordinated their research effort according to the specific objectives of the project, to develop and apply the two complementary methods for quality control of agricultural commodities. In Israel: An improved firmness testing system was developed and tested with tropical fruits. The new system included an instrumented fruit-bed of three flexible piezoelectric sensors and miniature electromagnetic hammers, which served as fruit support and low-energy excitation device, respectively. Resonant frequencies were detected for determination of firmness index. Two new acoustic parameters were developed for evaluation of fruit firmness and maturity: a dumping-ratio and a centeroid of the frequency response. Experiments were performed with avocado and mango fruits. The internal damping ratio, which may indicate fruit ripeness, increased monotonically with time, while resonant frequencies and firmness indices decreased with time. Fruit samples were tested daily by destructive penetration test. A fairy high correlation was found in tropical fruits between the penetration force and the new acoustic parameters; a lower correlation was found between this parameter and the conventional firmness index. Improved table-top firmness testing units, Firmalon, with data-logging system and on-line data analysis capacity have been built. The new device was used for the full-scale experiments in the next two years, ahead of the original program and BARD timetable. Close cooperation was initiated with local industry for development of both off-line and on-line sorting and quality control of more agricultural commodities. Firmalon units were produced and operated in major packaging houses in Israel, Belgium and Washington State, on mango and avocado, apples, pears, tomatoes, melons and some other fruits, to gain field experience with the new method. The accumulated experimental data from all these activities is still analyzed, to improve firmness sorting criteria and shelf-life predicting curves for the different fruits. The test program in commercial CA storage facilities in Washington State included seven apple varieties: Fuji, Braeburn, Gala, Granny Smith, Jonagold, Red Delicious, Golden Delicious, and D'Anjou pear variety. FI master-curves could be developed for the Braeburn, Gala, Granny Smith and Jonagold apples. These fruits showed a steady ripening process during the test period. Yet, more work should be conducted to reduce scattering of the data and to determine the confidence limits of the method. Nearly constant FI in Red Delicious and the fluctuations of FI in the Fuji apples should be re-examined. Three sets of experiment were performed with Flandria tomatoes. Despite the complex structure of the tomatoes, the acoustic method could be used for firmness evaluation and to follow the ripening evolution with time. Close agreement was achieved between the auction expert evaluation and that of the nondestructive acoustic test, where firmness index of 4.0 and more indicated grade-A tomatoes. More work is performed to refine the sorting algorithm and to develop a general ripening scale for automatic grading of tomatoes for the fresh fruit market. Galia melons were tested in Israel, in simulated export conditions. It was concluded that the Firmalon is capable of detecting the ripening of melons nondestructively, and sorted out the defective fruits from the export shipment. The cooperation with local industry resulted in development of automatic on-line prototype of the acoustic sensor, that may be incorporated with the export quality control system for melons. More interesting is the development of the remote firmness sensing method for sealed CA cool-rooms, where most of the full-year fruit yield in stored for off-season consumption. Hundreds of ripening monitor systems have been installed in major fruit storage facilities, and being evaluated now by the consumers. If successful, the new method may cause a major change in long-term fruit storage technology. More uses of the acoustic test method have been considered, for monitoring fruit maturity and harvest time, testing fruit samples or each individual fruit when entering the storage facilities, packaging house and auction, and in the supermarket. This approach may result in a full line of equipment for nondestructive quality control of fruits and vegetables, from the orchard or the greenhouse, through the entire sorting, grading and storage process, up to the consumer table. The developed technology offers a tool to determine the maturity of the fruits nondestructively by monitoring their acoustic response to mechanical impulse on the tree. A special device was built and preliminary tested in mango fruit. More development is needed to develop a portable, hand operated sensing method for this purpose. In North Carolina: Analysis method based on an Auto-Regressive (AR) model was developed for detecting the first resonance of fruit from their response to mechanical impulse. The algorithm included a routine that detects the first resonant frequency from as many sensors as possible. Experiments on Red Delicious apples were performed and their firmness was determined. The AR method allowed the detection of the first resonance. The method could be fast enough to be utilized in a real time sorting machine. Yet, further study is needed to look for improvement of the search algorithm of the methods. An impact contact-pressure measurement system and Neural Network (NN) identification method were developed to investigate the relationships between surface pressure distributions on selected fruits and their respective internal textural qualities. A piezoelectric dot-matrix pressure transducer was developed for the purpose of acquiring time-sampled pressure profiles during impact. The acquired data was transferred into a personal computer and accurate visualization of animated data were presented. Preliminary test with 10 apples has been performed. Measurement were made by the contact-pressure transducer in two different positions. Complementary measurements were made on the same apples by using the Firmalon and Magness Taylor (MT) testers. Three-layer neural network was designed. 2/3 of the contact-pressure data were used as training input data and corresponding MT data as training target data. The remaining data were used as NN checking data. Six samples randomly chosen from the ten measured samples and their corresponding Firmalon values were used as the NN training and target data, respectively. The remaining four samples' data were input to the NN. The NN results consistent with the Firmness Tester values. So, if more training data would be obtained, the output should be more accurate. In addition, the Firmness Tester values do not consistent with MT firmness tester values. The NN method developed in this study appears to be a useful tool to emulate the MT Firmness test results without destroying the apple samples. To get more accurate estimation of MT firmness a much larger training data set is required. When the larger sensitive area of the pressure sensor being developed in this project becomes available, the entire contact 'shape' will provide additional information and the neural network results would be more accurate. It has been shown that the impact information can be utilized in the determination of internal quality factors of fruit. Until now,
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