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Tytuł:
Acousto-Electromagnetic Analogies in Diffraction Phenomena Occurring in the Semi-Infinite Cylindrical Waveguide
Autorzy:
Snakowska, A.
Powiązania:
https://bibliotekanauki.pl/articles/1807756.pdf
Data publikacji:
2009-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
41.20.Jb
43.20.Wd
Opis:
The paper presents analogies between acoustic and electromagnetic wave field occurring in limited areas, such as waveguides, when electromagnetic waves are not purely transversal. The acousto-electromagnetic analogies exist in structures such as plane, rectangular or cylindrical infinite waveguides, if the fields are analysed by means of potentials - the velocity potential for sound waves and the Hertz potentials for electromagnetic waves. It has been demonstrated why these analogies between the potentials representing solutions of the wave equation with adequate boundary conditions and expressed as sums of admissible duct modes do fail, in general, for the semi-infinite cylindrical duct, and why they remain valid when the propagating electromagnetic mode is axisymmetric.
Źródło:
Acta Physica Polonica A; 2009, 116, 3; 410-413
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
An Insight into Coherent Backscattering Evaluation Techniques of Prospective Use in High Frequency Polarimetric Radar Image Processing
Autorzy:
Kapelewski, J.
Powiązania:
https://bibliotekanauki.pl/articles/1506794.pdf
Data publikacji:
2010-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
41.20.Jb
03.50.De
Opis:
Coherence in multiple scattering is important as it applies to imaging and detection of object in multiple scattering environments. These phenomena may also be used to investigate images of objects obscured by them. The scattering observations using very rough surfaces can provide useful insight into their statistic as they lie outside the range of validity of the standard theories. Recently, there has been growing interest in the phenomenon of backscattering enhancement in the reflection of electromagnetic waves of mm wave range from both atmospheric hydrometeors (rain, snow and precipitation) as well as very rough surfaces (including that of sea and terrain sea). Strong backscattering enhancement of mm waves incident at different incident angles, both in the TE and TM polarizations, was observed experimentally. In the paper a short description of specific techniques used for treating image processing of strongly irregular media is shortly presented. An emphasis is placed on the phenomena of interest in advanced polarimetric radar especially in mm wave range.
Źródło:
Acta Physica Polonica A; 2010, 118, 6; 1161-1167
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Confined Metamaterial Structures Based on Coordinate Transformations
Autorzy:
Vasić, B.
Gajić, R.
Isić, G.
Hingerl, K.
Powiązania:
https://bibliotekanauki.pl/articles/1807844.pdf
Data publikacji:
2009-07
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
03.50.De
41.20.Jb
42.70.-a
Opis:
We apply transformation optics to structures in which the electromagnetic field is confined by highly conducting coatings. The possibility of changing the field propagation direction without perturbation is demonstrated on the example of a waveguide bend. Using this approach it is also possible to reshape a confined structure in order to meet certain external requirements and to redistribute a field in order to obtain desired field distribution. The structure implementation implies replacing a part of given confined structure with a metamaterial designed using the technique of transformation optics. Simplification of structure realization based on using reduced set of material parameters is examined. Our theoretical considerations are confirmed by full wave finite element simulations of a waveguide bend.
Źródło:
Acta Physica Polonica A; 2009, 116, 1; 96-98
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Consequences of Unit Cell Design in Metamaterial Perfect Absorbers
Autorzy:
Bagci, F.
Akaoglu, B.
Powiązania:
https://bibliotekanauki.pl/articles/1398784.pdf
Data publikacji:
2016-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
81.05.Xj
41.20.Jb
Opis:
Metamaterials are a new class of composite materials with unusual properties that allow controlling of electromagnetic waves by properly engineering the response functions, which are not observed in constituent materials. However, since absorption of metamaterials is mainly based on electromagnetic resonances, the operating bandwidth is relatively narrow. Utilization of more than a single metallic structure with different geometrical parameters in each unit cell is a common way of accomplishing multiple band and/or broadband absorption. There are two usual approaches for this purpose: (a) multilayer unit cell design where metallic structures on dielectric substrate are stacked one on top of the other; (b) side by side unit cell design where metallic structures are distributed on a dielectric substrate. However, to the best of our knowledge, these two different approaches are not comparatively investigated. In this study, we propose metamaterial-based perfect absorbers with two different unit cell designs and simulate transmittances, reflectances and absorbances for each design by a commercial electromagnetic solver, CST Microwave Studio. It is found that each design has its own advantages in terms of device thickness, absorption bandwidth and angular dependence, which might be severely important for particular purposes.
Źródło:
Acta Physica Polonica A; 2016, 129, 4; 792-796
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Coupled Waves in Two-Phase Periodic Planar Multilayers
Autorzy:
Kapelewski, J.
Powiązania:
https://bibliotekanauki.pl/articles/1493229.pdf
Data publikacji:
2011-10
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
41.20.Jb
43.20.Mv
03.50.De
Opis:
In the paper a consequently dynamic model approach to the magnetoelectric coupling is proposed. As opposed to the static case the approach includes both the elastic equation of motion and the full set of the Maxwell equations for effective composite medium. The analytical treatment is performed from two layers of $\infty_m$ symmetry and results in closed relations for propagation characteristics of coupled elasto-electrodynamic waves for millimeter-length range.
Źródło:
Acta Physica Polonica A; 2011, 120, 4; 647-650
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Determination of Electromagnetic Emitter Position from Passive Radar Bearings as Linear Least Squares Problem
Autorzy:
Kawalec, A.
Kojdecki, M.
Wajszczyk, B.
Powiązania:
https://bibliotekanauki.pl/articles/1506796.pdf
Data publikacji:
2010-12
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
41.20.Jb
03.50.De
Opis:
Mathematical formulation of an inverse problem of radiolocation is discussed. Determination of electromagnetic emitter position from passive radar bearings is transformed into a linear least squares problem and equivalent system of normal equations. Eventually spatial localisation of emitter is reduced to solving system of linear algebraic equations with entries of coefficient matrix and free term depending on bearings in a nonlinear way. Regularisation algorithm is proposed.
Źródło:
Acta Physica Polonica A; 2010, 118, 6; 1171-1173
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Dispersion of Bloch Modes in a Multilayer Structure with Alternating Left-Handed and Right-Handed Materials
Autorzy:
Vukovic, S.
Aleksic, N. B.
Timotijevic, D. V.
Powiązania:
https://bibliotekanauki.pl/articles/2047883.pdf
Data publikacji:
2007-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
41.20.Jb
78.66.Fd
78.68.+m
Opis:
We study all-evanescent eigenmodes of a one-dimensional infinite periodic structure with alternating left-handed and right-handed materials that propagate perpendicularly to the surface or guided eigenmodes. Investigation of dispersion properties of such Bloch modes is shown to be crucial for understanding of an efficient radiation energy transport across the periodic multilayer structure. Frequency pass bands and gaps are found as a function of the two orthogonal wave vectors: the Bloch wave vector k$\text{}_{B}$ and the surface wave vector k$\text{}_{S}$. We demonstrate that pass bands of both TE- and TM-polarizations can exist and, under certain conditions, may overlap.
Źródło:
Acta Physica Polonica A; 2007, 112, 5; 1061-1066
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Effects of Loss Factor on Plane Wave Propagation through a Left-Handed Material Slab
Autorzy:
Sabah, C.
Powiązania:
https://bibliotekanauki.pl/articles/1812347.pdf
Data publikacji:
2008-06
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
04.30.Nk
41.20.Jb
78.20.Ci
Opis:
This article presents a theoretical and numerical discussion of the reflection and transmission analysis through a lossy left-handed material slab embedded between two semi-infinite dielectric media. The properties of the lossy left-handed material are given in detail and the required equations for the electromagnetic plane wave propagation are derived to solve the problem. The main important contribution of this article is the characterization of left-handed material that is different from its counterpart known in the literature. After introducing the left-handed material slab, the analytical solution is found for the powers carried by an electromagnetic wave. Then, the reflected, the transmitted, and the loss power are computed in terms of the incidence angle, the frequency, and the slab thickness in the numerical results with the emphasis on the loss factor.
Źródło:
Acta Physica Polonica A; 2008, 113, 6; 1589-1597
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electromagnetic Wave Behaviour in Uniaxial Magnetodielectric Media of 1+1>2 Type
Autorzy:
Kapelewski, J.
Dukata, A.
Powiązania:
https://bibliotekanauki.pl/articles/1807729.pdf
Data publikacji:
2009-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
41.20.Jb
43.20.Mv
03.50.De
Opis:
In the paper a phenomenological approach is proposed to polarized electromagnetic wave propagation in magnetodielectric media, composed of piezoelectric and magnetostrictive anisotropic monolayers. The composite materials consisting of a system of such bimorph films have recently attracted much interest, because they can exhibit a much stronger magnetoelectric effect in a wide temperature range than the single phase multiferroic materials. In the paper dispersion equations given in a common form for both TE and TM modes are derived for long wave approximation. The equations can be of use in evaluation of directional dependence for particular polarizations, which is of particular interest in designing substrate for miniaturized polarimetric antenna, especially useful for modern synthetic aperture radar systems.
Źródło:
Acta Physica Polonica A; 2009, 116, 3; 331-334
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Electromagnetic Waves Absorption by Graphene-Magnetic Semiconductor Multilayered Nanostructure in External Magnetic Field: Voight Geometry
Autorzy:
Kuzmin, D.
Bychkov, I.
Shavrov, V.
Powiązania:
https://bibliotekanauki.pl/articles/1386985.pdf
Data publikacji:
2015-02
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
41.20.Jb
42.25.Bs
68.65.Ac
68.65.Cd
68.65.Pq
Opis:
Absorption of electromagnetic waves by graphene-magnetic semiconductor multilayered structure has been investigated for the Voight geometry with taking into account the dissipation processes. The possibility of control of electrodynamic properties of the structure by an external magnetic field, changing in number of periods of the structure, chemical potential of the graphene layers and temperature has been shown. Electrodynamics of the structure is also sensitive to polarization of the incident wave. The structure shows to be especially controllable at terahertz frequencies.
Źródło:
Acta Physica Polonica A; 2015, 127, 2; 528-530
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Exact Phase and its Eikonal Approximation for Class of Reflectionless Index Profiles
Autorzy:
Sharma, S. K.
Ghosh, G.
Powiązania:
https://bibliotekanauki.pl/articles/1963260.pdf
Data publikacji:
1997-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
42.25.Fx
41.20.Jb
Opis:
We examine the problem of transmission of electromagnetic waves in a multiparameter reflectionless dielectric. It is shown that it is possible to obtain an analytic form for the phase of the exact transmission amplitude. In the high frequency limit the exact result is found to lead to the eikonal approximation. Interestingly, the high frequency limit and long-range approximation required for the validity of the eikonal approximation are not independent here.
Źródło:
Acta Physica Polonica A; 1997, 91, 3; 555-561
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Frequency stop band in an air-voided ZnO photonic crystal: A dispersion diagram based design
Autorzy:
Chaturvedi, V.
Kumar Roy, M.
Powiązania:
https://bibliotekanauki.pl/articles/1075558.pdf
Data publikacji:
2016-09
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
01.65.+g
01.70.+w
41.20.Jb
78.20.-e
Opis:
Electromagnetic excitation, inside small volumes, results in perturbations which play an important role in the validation of theoretical formulations. Efforts to catch a glimpse of the action inside of the small space, can aid better thin film designs. In the non-linear anisotropic regime the results of such interactions provide important insights into the bulk level behavior of matter. Using this approach, a zinc oxide (ZnO) based photonic crystal is designed with spherical air voids. A Gaussian continuous wave excitation of the refractive index contrast (ZnO=1.9 and Air =1) photon waveguide generated thus, is characterized for the redistribution of electromagnetic field. When, centered at a specific wavelength (1.9 μ m), the graph of the frequencies that can exist inside the crystal, is plotted against the limited k-space vector. The dispersion diagram that emerges shows a band of frequency states that cannot exist inside such a design. Physically this constitutes a k-space which is devoid of any detectable disturbances. Crystallographically, the reduced Brilluoin zone can be used to make a thin layer of ZnO that can act as a frequency stop layer, in a real multilayered photoelectric device.
Źródło:
Acta Physica Polonica A; 2016, 130, 3; 683-687
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
High-Frequency Absorbing Performances of Carbonyl Iron/MnZn Ferrite/PVC Polymer Composites
Autorzy:
Dosoudil, R.
Ušáková, M.
Powiązania:
https://bibliotekanauki.pl/articles/1032831.pdf
Data publikacji:
2017-04
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
75.50.Gg
75.50.Bb
76.50.+g
75.78.-n
72.80.Tm
78.20.Ci
41.20.Jb
Opis:
We have prepared composite materials with a mixture of carbonyl iron (CI) and manganese-zinc ferrite (MnZn) as filler and polyvinylchloride (PVC) as polymer matrix, and then electromagnetic wave absorption properties of CI/MnZn/PVC composites have been studied in the frequency range from 10 MHz to 6.5 GHz. Increasing carbonyl iron loading (to the detriment of MnZn ferrite) results in the rise of permeability and magnetic resonance loss (especially in GHz frequency range) which leads to the shift of absorption peak towards lower frequency and to the decrease of matching thickness. On the contrary, increasing MnZn ferrite loading (to the detriment of carbonyl iron) results in higher absorption bandwidth. The obtained results indicate that the prepared flexible composites may be useful as thin and/or wideband microwave absorbers.
Źródło:
Acta Physica Polonica A; 2017, 131, 4; 687-689
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Imperfect Cloaking Devices Based on Metamaterials
Autorzy:
Isić, G.
Gajić, R.
Novaković, B.
Popović, Z. V.
Hingerl, K.
Powiązania:
https://bibliotekanauki.pl/articles/2047887.pdf
Data publikacji:
2007-11
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
41.20.Jb
42.25.Fx
78.20.Ci
Opis:
Cloaking devices designed using the coordinate transform approach were shown to be realizable, at least in principle, within the realm of electromagnetic metamaterials. In this paper we investigate the strictness of conditions imposed on the parameters of metamaterial cloaks by calculating the degree of wave scattering when those parameters have variations with respect to theoretically ideal values. A simple idea is used to obtain analytic results for the case of the nonideal two-dimensional cloaking cylinder. Also, results of realistic finite element simulations of the Helmholtz equation are presented and it is found that they are in excellent agreement with the analytic results.
Źródło:
Acta Physica Polonica A; 2007, 112, 5; 1083-1088
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Tytuł:
Investigation of Electromagnetic Wave Absorber Based on Carbon Fiber Reinforced Aerated Concrete Using Time-Domain Method
Autorzy:
Laukaitis, A.
Sinica, M.
Balevičius, S.
Levitas, B.
Powiązania:
https://bibliotekanauki.pl/articles/1813404.pdf
Data publikacji:
2008-03
Wydawca:
Polska Akademia Nauk. Instytut Fizyki PAN
Tematy:
41.20.Jb
81.05.Uw
Opis:
The electromagnetic wave absorbers prepared from autoclaved aerated concrete containing carbon fibers as additions in the shape of slabs with pyramids cut on one plane of these slabs were tested using dc microwave source and the time-domain method. It was demonstrated that autoclaved aerated concrete allows one to fabricate electromagnetic wave absorbers which have a reflection coefficient up to -30 dB in the frequency range from 2 GHz to 18 GHz.
Źródło:
Acta Physica Polonica A; 2008, 113, 3; 1047-1050
0587-4246
1898-794X
Pojawia się w:
Acta Physica Polonica A
Dostawca treści:
Biblioteka Nauki
Artykuł
Wyświetlanie 1-15 z 40

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