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Antenna Theory and Techniques (ICATT), 2011 VIII International Conference on

Date 20-23 Sept. 2011

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Displaying Results 1 - 25 of 85
  • Table of contents

    Page(s): vii - xi
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    Freely Available from IEEE
  • Antenna science atlantes

    Page(s): 3 - 7
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    The paper is devoted to memory of three outstanding scientists Aleksander A. Pistolkors, Efim G. Zelkin and Lev D. Bakhrakh, whose jubilee dates fall on 2011. A brief story about their lives is given, namely about enormous services of each of them in creation of the modern antenna theory foundations, in the development of many original antenna systems, in writing fundamental antenna text-books and monographs with which many thousands of highly skilled antenna specialists of different generations have studied. Significant attention is also paid to description of their tireless and many-sided scientific-organizational activities that essentially favored creation of amicable antenna community in the USSR. The paper is mainly based on remembrances of its authors who used to be tightly related during several decades to each of persons whose jubilees are celebrated. View full abstract»

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  • Recent advances in antenna research and development at the National Technical University of Ukraine “Kyiv Polytechnic Institute”

    Page(s): 8 - 12
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    This paper highlights recent advances in research, development, designing, manufacturing and testing of different types of high performance antenna arrays, horns, feed systems and flexible polarization reflector antennas for application in modern radars and communication systems achieved by the Microwave Antenna Group at National Technical University of Ukraine "Kyiv Polytechnic Institute". View full abstract»

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  • Biochemical observational science at THz energies

    Page(s): 13 - 18
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    In this overview we will explore how current terahertz (THz) and sub-THz experimental systems are being used in a variety of ways to visualise and indeed, controllably excite biochemical processes. For example, a contributing cause to disease is known to be due to mis-folding proteins. But how proteins fold in order to perform a biological task is a deep mystery. The difficulty in understanding what happens comes from not being able to 'see' clearly what happens experimentally. Sub-THz spectrometry based on high resolution systems (vector network analysers) can record vibrational modes from absorption spectra. Antenna engineering presents biology with a means for understanding their molecular systems as equivalent electrical circuits. From the measured frequency absorption spectra of the protein we seek to learn from the protein's vibrational structure, its folding trajectory. Finally we will look at how deliberate, targeted, excitation of specific vibrational modes of molecules can be used to effect new reaction pathways to create an intelligent and engineered approach to RF-assisted chemistry. View full abstract»

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  • Studies on radar medical sensors

    Page(s): 19 - 21
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    Ultra-wideband (UWB) radar enables detection and imaging of electrically contrast dielectric and conducting objects inside the human body that can be used to detect tumors, internal wounds and support other medical diagnosis along with mapping different metal/dielectric inclusions to navigate, e.g. a robotic surgical tool. General principles to design such systems and their building blocks are discussed along with implementation challenges. Two biomedical test radar systems are described to illustrate the study. View full abstract»

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  • Large-aperture slotted-waveguide antenna arrays: Development and fabrication advances

    Page(s): 22 - 27
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    An efficient approach to the synthesis of large-aperture slotted-waveguide antennas (SWA) is proposed. The approach is based on a combined usage of a full wave simulation and physical properties of SWA. The proposed approach was applied to the development of a large-aperture Ka-band antenna with a 1 meter aperture. The obtained antenna gain is close to the theoretical maximum for such aperture. The antenna is also characterized by a relatively wide frequency operational range that is achieved by application of the subarraying technique. The influence of the systematic and random manufacturing errors on the antenna performance is investigated. A comparison of the simulation results with the antenna measurement results is presented as well. View full abstract»

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  • Near-field manipulation by means of wire media

    Page(s): 28 - 33
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    A medium formed by arrays of metallic wires can transmit, magnify, and de-magnify near-field distributions with sub-wavelength resolution. It is shown that sub-wavelength images with a resolution of one-fifteenth of a wavelength can be transferred to a distance of three wavelengths with a threefold magnification/demagnification. Also, embedding a dielectric phase compensator in the tapered array to compensate the phase differences introduced by the different lengths of wires and significantly improves the operational bandwidth of the image transmission and magnification device have been proposed, finally, various microwave applications of wire media near-filed manipulations are demonstrated. View full abstract»

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  • Vehicular antennas for satellite communications

    Page(s): 34 - 39
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    Antennas mounted at vehicles for satellite communications and direct broadcasting service are considered in the paper. The antennas have scanning beams with high gain as well as satellite tracking capabilities. Such antenna provides a wideband communication link via a satellite while a vehicle is in motion. Antennas are mounted on cars, buses, trains, ships, airplanes, etc. General requirements to vehicular antennas are discussed in the paper. Main concepts of vehicular tracking antenna design are described. They are: active phased array antenna with 2-D electrical beam steering, planar array with mechanical rotation in azimuth and 1-D electrical scanning in elevation, and a reflector antenna or a planar array on a 2-D positioner providing mechanical beam scanning. A survey on vehicular antennas developed worldwide in last decades is presented. Main trends of the antennas are discussed. View full abstract»

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  • Synthesis of arbitrarily shaped impedance reflectors

    Page(s): 40 - 45
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    A rigorously stated synthesis problem of inhomogeneous stationary and quasi- stationary impedance planes, which reflect a homogeneous flat wave in the given direction at the required polarization with a frequency shift, is solved. The impedance distribution law is obtained in the explicit form. Restrictions on class of realizable scattering patterns for passive impedance are formulated; formulas for the reflection coefficient of the flat wave reflected by the inhomogeneous impedance plane are developed. Bistatic and monostatic scattering patterns are considered. View full abstract»

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  • Wavefield control in multimode channels by the use of source arrays, with application to shallow-water sound

    Page(s): 46 - 50
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    An intrinsic feature of the long-range signal propagation in random-inhomogeneous multimode waveguides is well known to be the signal loss and coherence degradation. These key factors are both dependent on the signal modal spectrum due to the fact that the signal-carrying modes essentially differ in their decay coefficients and effects on the signal fluctuations and the coherence length both in temporal and spatial domains (for a given distance from the source). Moreover, the output performance of signal processing against the nose background in such a scenario is also critical to the modal interference if this noise is intensive enough as is compared with the non-modal (for example, iso- tropic) ambient noise and/or sensor noise of the receiving system. In this paper, we give a short overview of our recent research focused on the effective wavefield control in multimode channels by the use of source arrays, the amplitude-and-phase distributions of which vary to control the signal modal spectrum at the channel 'input'. The field experiments have been realized in a typical shallow-water sound channel, and their results show the practical application of the approach presented. View full abstract»

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  • Thirty years experience in development of adaptive lattice filters theory, techniques and testing in Kharkiv

    Page(s): 51 - 56
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    Common elements of different problems on space-time adaptive processing of Gaussian signal and a place of adaptive lattice filters (ALF) in their solution are discussed. Discussed are the ALF advantages in comparison with other analogous purpose filters; results of their modeling, scaled-down and scaled testing in adaptive systems of clutter protection and meteorological formation spectrum estimation in operating radars; peculiarities of practical realization on the basis of modern digital elemental base. View full abstract»

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  • Evolution of electromagnetic waves radiated by a Hertzian dipole

    Page(s): 63 - 68
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    Evolution of electromagnetic waves, despite their use for more than century, is still not known. It was written much about poor understanding of the nature of electromagnetic waves. For example, Nobel Prize R. Feynman [1] writes: "... I must confess that we did not know what is actually allocated to the electromagnetic field energy." In a paper [2] in 1905 A. Einstein wrote: "We intend to make an additional assumption, ... ... that the light in a vacuum always propagates with a certain velocity v, independent of the state motion of the radiation source." This "additional assumption" later turned into a principle tenet of which even today many scientists consider true. I think that appearing of some new theories, which, as noted by M. Klein [3], " Work the mathematical rules and intelligent interpretation ... of the world, sadly, no" caused, in particular, the lack of clear, deep understanding of the nature and evolution of electromagnetic waves. In literature, the definition of these concepts is given, based on the concept of "plane wave" wave at a great distance from the radiator (in the far-field zone), where it is formed as a whole. At distances from the radiator to the far-field zone, these characteristics have been not studied. The purpose of this study is to clarify the evolution of electromagnetic waves, clarification of the basic concepts of electrodynamics, for example, waves radiated by the Hertzian radiator. View full abstract»

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  • Numerical-analytical implementation of Galerkin technique for analysis of waveguide and slotted waveguide antenna arrays

    Page(s): 69 - 74
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    A novel fast and accurate full-wave approach to the analysis of a wide class of slotted waveguide arrays and finite multi-layer waveguide arrays with dielectric cover is presented. The numerical-analytical solution is based on Galerkin method with weighted Chebyshev and Gegenbauer polynomials as basis functions explicitly accounting for the field asymptotic at the edges. An extremely fast convergence of the method is achieved due to proper basis functions. The other key point of the solution is the computational acceleration of double series and integrals which are the matrix elements of a final system of linear algebraic equations. The results for traveling-wave array with shunt slots for radar applications are considered. A parametric study of waveguide antenna arrays with finite multi-layer dielectric cover is presented, which includes the effect of dielectric cover on impedance matching, array efficiency and directivity. View full abstract»

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  • To history of radio engineering'S term "antenna"

    Page(s): 83 - 85
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    Results of the researches directed on finding-out of a true state of affairs in the history of origin of radio engineering's term of "antenna" are presented in the report. As a result of this report can be considered that the first document, we are aware of that uses the word l'antenne for an electromagnetic transmitter, is a paper by Lucien Poincare, presented in 30 January 1898 at a Revue generate des sciences pures et appliquees. This paper by Lucien Poincare contained information that Marconi was the author of radio engineering's term "antenna". It is shown that radio engineering's term "antenna" was introduced by Marconi, but a main role in expansion of this term to modern radio engineering has an publications of France's scientists Lucien Poincare, Andre Broca and A. E. Blonde!. View full abstract»

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  • The energy of the field radiated by Hertz dipole

    Page(s): 86 - 88
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    All components of electromagnetic field radiated from Hertz dipole excited by current with arbitrary time dependence are obtained in time domain by means of vector Hertz technique. The processes of transformation of quasistatic components of field into electromagnetic wave are investigated. The problem of radiation of Hertz dipole with quickly decreasing dipole moment from some constant value to zero is considered. The questions of describing the process of the forming of free electromagnetic field from quasistatic field components in near field zone of dipole are discussed. View full abstract»

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  • Shape transformation of wave beams falling on quasiperiodic layered structures

    Page(s): 89 - 91
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    Bragg structures with distortion of periodicity are considered. Effects of scattering the wave beams falling at oblique angles are theoretically investigated. Methods of characteristic matrices and plane-wave decomposition are used for obtaining angular and spatial distribution of reflected and transmitted wave beams. Magnitudes and phases of scattered fields are analyzed. Phenomena of anomalous behavior of group shifts (decreasing and negative ones) are observed for Bragg structures with different type of periodicity distortions. View full abstract»

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  • Orientation and dispersion diagrams of spatially-polarizing selective structures in the form of the cylinder with the star contour

    Page(s): 92 - 94
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    The characteristics of radiation and dispersion of frequency-spatially-polarizing structures in the form of the cylinder with a star contour are investigated in the report. Physical bases of occurrence of selective properties are considered. The interrelation of pattern of scattering and structure parameters (radius of the cylinder, number and depth of hollows) is analyzed. View full abstract»

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  • Spectrum extrapolation for complex sources via two-channel version of a principle of minimal spatial extension of solution

    Page(s): 97 - 99
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    Problem of spatial spectrum extrapolation is considered. Method of minimal spatial extension of solution is used. Two-channel version of functional of quasi-extension is proposed. Case of complex point sources is investigated. Reduction of errors is observed in comparison with one-channel version. View full abstract»

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  • Coupled plasma cylindrical columns as sub-wavelength antenna

    Page(s): 103 - 105
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    We theoretically study the resonant properties of an aggregate of coupled cylinders filled with negative permittivity plasma. Such a problem has applications in optical and plasma antennas, intelligent antenna systems, and pulse-driven antenna arrays. Chain of columns of plasma can be used in the design of both transmitting and receiving antennas with a very broad frequency range and tunability that allows switching it on and off very fast. The Mie series expansion is used to derive the solution. Electromagnetic analysis of the spectrum of different plasmon resonances is presented. View full abstract»

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  • Diffraction problem in bistatic zone of radio acoustic sounding systems

    Page(s): 112 - 114
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    A number of problems retards introduction of the radio acoustic sounding method into the meteorological observations practice. The lack of rigorous solution to the problem of electromagnetic waves diffraction on the artificial reflector formed with acoustic waves beam limited in space is among them. The general solution is rather cumbersome. The modern state of theoretical representations is shown. The approaches tolerable in the given problem are discussed in terms of the antenna theory. The report presents results of solving the diffraction problem in the bistatic zone. Variation of level of a received signal is shown as a function of the sounding altitude (function of radial interaction of fields). View full abstract»

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  • Detection of solid Earth excitations by laser seismo-acoustic antenna array

    Page(s): 117 - 119
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    The spatial and temporal distributions of seismo-acoustic wave fields are investigated. Non-stationary parameters (direction to the sources of oscillations, their intensities and localization) have been studied and estimated. The wave field distribution in elastic solid medium is recorded by the array of strain sensitive units. Every strain detector represents the laser interferometer with base-length 1-400 m, which measures the distant difference between two points of the solid medium. In this way spatial and temporal distribution of a strains field is being evaluated. The output signals of every laser sensors supplies the consequent inputs of multi-channel analog-to-digital converter and the obtained data are stored and subjected to the processing in the PC. The procedure of numerical treatment is based on the Fourier spectral analysis, which results to the tracks of non-stationary source motions to be displayed. The examples of described procedure for laser interferometers being apart up to 140 km and obtained data are presented. View full abstract»

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  • Noise-protected antenna for a pulse acoustic atmospheric sounder

    Page(s): 120 - 122
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    Antenna systems of modern acoustic atmospheric sounding technique (SODAR) are among the most functionally important and expensive of its constituents. The successful versatile SODAR application is directly related to the high-quality indexes of the acoustic antenna, such as noise protection in relation to acoustic ambient noise. In the present work, on an example of worked out by authors SODAR, the questions of acoustic noise protected hybrid budget antenna creation are considered in a practical way. Main attention is given to the original construction of transceiving acoustic phased array which is a constituent of the antenna. View full abstract»

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  • The effect of defective radiators and modules on characteristics of array antenna with complex aperture and multi-faceted array antenna

    Page(s): 126 - 128
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    The array antenna consisting of rectangle form subarrays (modules) is considered. Modules are placed in space in two ways: on the plane and on the lateral surface of a cylinder, forming a multi-faceted array antenna. The effect of number of array's defective radiating elements (individual radiators or modules) on antenna pattern parameters and antenna directivity is investigated. Three forms of flat array's aperture are considered: rectangle, elliptical and octagonal. The numerical simulation is used for analysis. Defective radiating element is referred to as that one, which has zero excitation amplitude. Defective elements are placed on the antenna's surface randomly. View full abstract»

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  • The influence of interchannel and intrachannel nonidentities on antenna array characteristics

    Page(s): 129 - 131
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    The influence of interchannel and intrachannel non-identities on digital antenna array characteristics is studied. Non-identities are random amplitude and phase excitation errors of receive/transmit modules. Cases of fast and slow fluctuations of random errors are considered. Variation frequency of fast fluctuations is much greater than scanning frequency. Variation frequency of slow fluctuations is much less than frequency of scanning. View full abstract»

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  • Characteristics of linear slotted waveguide arrays on the rectangular waveguide with two-layer dielectric filling at excitation by the slowed down dominant mode

    Page(s): 132 - 134
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    Linear systems of slots in a rectangular waveguide with the partial dielectric filling, excited by the slowed down wave are considered. The dielectric layer is parallel to wide walls of a waveguide. It is shown that not resonant system of longitudinal slots in a waveguide with a dielectric layer is more wideband in comparison with that in a hollow waveguide. For not resonant system of transversal slots possibility of scanning without interference maxima occurrence is shown. For resonant system of transversal slots possibility of one beam pattern formation is shown at almost full matching at the entrance. View full abstract»

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