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1
Content available remote

The Numerical Synthesis of a Radar Signal Based on Iterative Method

100%
Lesnik C., Kawalec A., Szugajew M.
Acta Physica Polonica A
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2011
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vol. 120
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issue 4
693-697
EN
This paper presents the impact of numerical methods used to solve the problem of synthesis of signals modulated in frequency with an autocorrelation function that implements an optimal approximation to a given autocorrelation function. After theoretical introduction an algorithm of frequency modulated signal synthesis is presented. Simulation results made in Matlab are presented in the last section.
2
Content available remote

Mode Analysis of the Optical and the Microwave Waveguides Using Electromagnetic Energy Flow Lines

63%
D. Davidović M., D. Davidović M.
Acta Physica Polonica A
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2009
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vol. 116
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issue 4
672-674
EN
To better elucidate the essential energy transmission mechanism in the most common, typical waveguides, the electromagnetic energy flow lines for a planar optical slab waveguide and a microwave rectangular waveguide are constructed. The obtained results supply more direct and transparent insight into the distribution of electromagnetic energy in the modes of various character.
3
Content available remote

On Electrodynamical Self-Interaction

63%
Kijowski J.
Acta Physica Polonica A
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1994
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vol. 85
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issue 4
771-787
EN
It is shown that the classical Maxwell theory admits a simple and natural renormalization of the self-interaction energy. This leads to a consistent, local and causal, relativistic theory of the Maxwell field interacting with classical, charged, point-like particles. The theory may be regarded as a simple and necessary completion of special relativity. The renormalization method proposed here is a realization of Einstein's idea of "deriving equations of motion from field equations". It is shown that Dirac's "3-dots" equation does not describe a fundamental law of physics, but only a specific family of solutions of our theory, corresponding to a specific choice of the field initial data.
4
Content available remote

Retardation in Special Relativity and the Design of a Relativistic Motor

63%
Yahalom A.
Acta Physica Polonica A
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2017
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vol. 131
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issue 5
1285-1288
EN
The Newton third law states that any action is countered by a reaction of equal magnitude but opposite direction. The total force in a system not affected by external forces is thus zero. However, according to the principles of relativity, a signal cannot propagate at speeds exceeding the speed of light. Thus the total force cannot be null at a given time. The above conclusion leads to the possibility of a relativistic engine in particular one that is based on a permanent magnet. The analysis is based on a previous paper in which we studied the relativistic effects in a system of two current conducting loops.
5
Content available remote

The Numerical Synthesis of a Radar Signal Having Required Autocorrelation Function

63%
Leśnik C., Kawalec A., Szugajew M.
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|
issue 6
1194-1198
EN
This paper presents the problem of synthesis of signals modulated in frequency with autocorrelation function that implements an optimal approximation to a given autocorrelation function. After theoretical introduction an algorithm of frequency modulated signal synthesis is presented. Simulation results made in Matlab are presented in the last section.
6
Content available remote

An Insight into Coherent Backscattering Evaluation Techniques of Prospective Use in High Frequency Polarimetric Radar Image Processing

63%
Kapelewski J.
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issue 6
1161-1167
EN
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.
7
Content available remote

Determination of Electromagnetic Emitter Position from Passive Radar Bearings as Linear Least Squares Problem

63%
Kawalec A., Kojdecki M., Wajszczyk B.
|
EN
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.
8
Content available remote

Split Octonions and Maxwell Equations

63%
Nurowski P.
Acta Physica Polonica A
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2009
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vol. 116
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issue 6
992-993
EN
A formulation of the Maxwell equations in terms of the split octonions is presented.
9
Content available remote

Wave Phenomena in High-Voltage Windings of Transformers

51%
Banaszak S., Gawrylczyk K.
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vol. 125
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issue 6
1335-1339
EN
Determination of mechanical condition of transformer active part can be performed utilizing frequency response of the windings. Many computing models were developed to evaluate behavior of the winding in wide frequency range using different numerical methods. Most of them utilizes finite elements, assuming axial symmetry, if possible. In other cases we need to use a three-dimensional model, which results in a significant reduction in the accuracy of modeling the geometry of the system, as well as the penetration of electromagnetic field into conductors. From a practical point of view, using computer of average performance, the windings can be modeled with at most 10 turns. From this reason mixed models are proposed, where the electric parameters of the winding are concentrated in the substitute RLC elements. Such models are known as "lumped parameter models". Since the parameters of real winding are distributed, the question arises concerning the necessity of taking into account wave phenomena in them. The method allowing this is known as "transmission line method". Measurements of frequency response are used in industry. There are still many problems with interpretation of test results. Computer modeling may be a helpful tool allowing to understand relation between the geometry of a winding and its frequency response. To fulfill this, models should give similar response as a real measurement. The paper describes a modified transmission line method used for modeling of a transformer winding's frequency response. There is described the model, its parameters, and exemplary solution compared to test data.
10
Content available remote

Design and Experimental Analysis of Rail Type Electromagnetic Weapons Systems

51%
Kakilli A., Yıldız İ.
Acta Physica Polonica A
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2015
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vol. 127
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issue 4
1150-1155
EN
In the study, electromagnetic weapon systems that are developed as an alternative to modern weapon systems are examined and a design for a rail type electromagnetic weapon system is intended. After a literature review on the subject, the comparison of electromagnetic and conventional weapons is made and models of electromagnetic weapons are elaborated. In the study, information of various electromagnetic weapons is provided but the focus is determined to be rail type electromagnetic weapons. Rail type electromagnetic weapons are examined in the study and the design of a low-power weapon prototype is made. For the model developed under laboratory conditions, 8 capacitors are used as a source of ignition. With the rail type electromagnetic weapon system designed, 2613.9 Joule energy is reached. The system components projected in theoretical calculations are enhanced throughout the application phase and are optimized for rail type weapon systems. For making theoretical studies and for drawing the graphs MATLAB software program is utilized. As a consequence, theoretical and empirical data is compared and commented, and some recommendations are formed.
11
Content available remote

Confined Metamaterial Structures Based on Coordinate Transformations

51%
Vasić B., Gajić R., Isić G., Hingerl K.
Acta Physica Polonica A
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2009
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vol. 116
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issue 1
96-98
EN
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.
12
Content available remote

An Experimental Study on Unipolar Induction

51%
Chen K., Li X., Hui Y.
Acta Physica Polonica A
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2017
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vol. 131
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issue 2
271-274
EN
Unipolar induction phenomenon is a special kind of electromagnetic induction. There are two quite opposite theoretical explanations for this phenomenon, i.e., the N theory and the M theory. The research of unipolar induction has made significant progress, but there is no final conclusion by now. In this paper, an experiment of inversely rotating double Faraday disks and double magnets are designed, and the unipolar induction phenomenon is verified by means of theoretical calculation and experiment. Comparing and analyzing the theoretical calculation and experiment results, our experimental results support the N theory, that is to say, our experiment shows that the magnetic field does not rotate when the magnet rotates.
13
Content available remote

On Generalized Landau Levels

51%
Krasoń P., Milewski J.
Acta Physica Polonica A
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2017
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vol. 132
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issue 1
94-96
EN
We consider the dispersion of energy levels for both standard and inverted quantum harmonic oscillators in the presence of a uniform electromagnetic field. For this analysis we use a solution of the corresponding eigenproblem in terms of the Kummer functions. We find a complete description of the energy levels for a particle of mass m and electric charge q subject to the action of a harmonic oscillator and simultaneous uniform magnetic and electric fields. We also analyze the effect of spin on energy levels for an electron.
14
Content available remote

Electromagnetic Wave Behaviour in Uniaxial Magnetodielectric Media of 1+1>2 Type

51%
Kapelewski J., Dukata A.
Acta Physica Polonica A
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2009
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vol. 116
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issue 3
331-334
EN
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.
15
Content available remote

New Results in Chaotic Time-Reversed Electromagnetics: High Frequency One-Recording-Channel Time-Reversal Mirror

51%
Anlage S., Rodgers J., Hemmady S., Hart J., Antonsen T., Ott E.
Acta Physica Polonica A
|
2007
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vol. 112
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issue 4
569-574
EN
We experimentally demonstrate a new electromagnetic one-recording-channel time-reversal mirror that can operate at high frequencies and high bandwidths. The experiments are carried out in a 1 m^3 ray-chaotic enclosure using two simple antennas. The input is a 7.0 GHz signal that is amplitude modulated with a 60 ns long pulse. The time-reversal focused signal has a peak-signal-to-noise ratio of about 9 dB, and is very sensitive to small perturbations to the ray-chaotic enclosure. The results are consistent with expectations for single-recording-channel time-reversal mirrors, and establish a new platform for study of fundamental issues in time-domain wave chaos, as well as novel applications.
16
Content available remote

Coupled Waves in Two-Phase Periodic Planar Multilayers

51%
Kapelewski J.
Acta Physica Polonica A
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2011
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vol. 120
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issue 4
647-650
EN
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 ∞_m symmetry and results in closed relations for propagation characteristics of coupled elasto-electrodynamic waves for millimeter-length range.
17
Content available remote

Anomalous Phase and Attenuation Constants of SiC Rod Waveguide at Higher Temperatures

51%
Acta Physica Polonica A
|
2013
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vol. 123
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issue 1
58-61
EN
Here we present the dependences of the phase and attenuation constants of silicon carbide (SiC) cylindrical rod waveguide upon frequency at different temperatures, i.e. T = 1800C and T = 1900C when the rod radius is relatively large. We have also calculated the electric and magnetic field distributions at different frequencies in order to explain the anomalous attenuation. The SiC rod waveguide was investigated by the partial area method. The complex roots have been found by the Müller method. Computer codes for calculations were written in MATLAB language.
18
Publication available in full text mode
Content available

Scattering of Light by Photonic Crystals

45%
Hoenders B., Doosje M., Knoester J.
Acta Physica Polonica A
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2002
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vol. 101
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issue 1
133-146
EN
A new method is developed to calculate the scattering of light at the surface of a photonic crystal. The problem is solved in terms of virtual surface-current distributions and the calculation takes full advantage of the infinite-space plane-wave expansion method for obtaining the photonic band structure. Working with surface currents makes the calculations less time-consuming by means of reduction of the dimensionality in the problem. The method is applied to a semi-infinite dielectric continuum and for semi-infinite two-dimensional photonic crystals of small and large dielectric contrast.
19
Publication available in full text mode
Content available

Aspects of the Scattering and Impedance Properties of Chaotic Microwave Cavities

38%
Hemmady S., Zheng X., Antonsen T., Ott E., Anlage S.
Acta Physica Polonica A
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2006
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vol. 109
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issue 1
65-71
EN
We consider the statistics of the impedance Z of a chaotic microwave cavity coupled to a single port. We remove the non-universal effects of the coupling from the experimental Z data using the radiation impedance obtained directly from the experiments. We thus obtain the normalized impedance whose probability density function is predicted to be universal in that it depends only on the loss (quality factor) of the cavity. We find that impedance fluctuations decrease with increasing loss. The results apply to scattering measurements on any wave chaotic system.
20
Content available remote

An Improvement of Magnetic Flux Linkage in Electrical Generator using the novel Permanent Magnet Arrangement

38%
Sriwannarat W., Khunkitti P., Janon A., Siritaratiwat A.
Acta Physica Polonica A
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2018
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vol. 133
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issue 3
642-644
EN
The partitioned stator permanent magnet generator (PS-PMG) has been extensively used as electrical generator due mainly to their high flux linkage, high electromotive force EMF) and high efficiency, especially the PM arrangement of the PS-PMG is an important factor to improve the performance of the generator. Therefore, we propose the novel permanent magnet PM) arrangement of the PS-PMG by using the dual rotor with coaxial core structure in order to improve the flux linkage and the EMF of PS-PMG. The PM position of stators of the conventional PS-PMG was rearranged, then the electrical characteristic of the proposed structure was characterized through the simulations based on finite element method. It was found that the flux linkage produced by the proposed structure is 37.06% higher than that of the conventional PS-PMG existed in the literatures because the area for induced flux linkage is significantly increased. This flux linkage enhancement further causes an increment of EMF about 34.95% compared to that of the conventional PS-PMG under the same condition. Especially, the EMF produced by the proposed structure is classified in the high-value range regarding the PM generator. Then, the PS-PMG using novel permanent magnet arrangement could be another remarkable choice for the electrical generator application
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