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Antennas and Propagation Magazine, IEEE

Issue 5 • Date Oct. 2003

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Displaying Results 1 - 16 of 16
  • Cellular telephone radiation and electroencephalograms (EEG) of the human brain

    Publication Year: 2003 , Page(s): 150 - 153
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (380 KB) |  | HTML iconHTML  

    Reports from several laboratories suggest that microwave radiation from cellular telephones could modify certain brain electrical activity under both awake and sleep conditions. However, the results were inconsistent. In particular, results of two series of studies from two different laboratories were most intriguing. A series of reports from one laboratory gave conflicting results on the influence of microwave radiation from cellular telephones on human EEG activity. In contrast, results from another laboratory not only extended their earlier findings that electromagnetic radiation from cellular telephones can affect human EEG activity, but suggested that pulse-modulated microwaves from cellular phones may promote sleep and modify human brain electrical activity. View full abstract»

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  • 20st century engineer-entrepreneur

    Publication Year: 2003 , Page(s): 106 - 114
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (760 KB)  

    The emerging facts from successful organizations, including universities, indicate that the real source of power in a knowledge-based economy is in combining technical prowess with entrepreneurship. This paper first highlights missing links in the aptitude and attitude of an engineer in combining technical knowledge with sound decision-making and effective entrepreneurship. Second, it discusses the gaps in traditional college education, and their remedies through outcome-based curricula. Third, it presents the distinction between leadership and management with reference to new models espoused in the theory of constraints (TOC). Fourth, it outlines the skills needed for the professional development of an individual to transform him or her from a traditional quantitative/verbal thinker to a future-oriented visionary by redirecting the whole-brain thinking. Finally, critical success factors in the development of an effective and efficient knowledge worker for the 21st century is enumerated. View full abstract»

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  • Static Green's functions with conformal mapping and MATLAB

    Publication Year: 2003 , Page(s): 123 - 135
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (800 KB) |  | HTML iconHTML  

    In this paper, conformal mapping was combined with Matlab. An application of the theory was showed in examples showing its ability to provide analytical expressions for two-dimensional Green's functions associated with Poisson's equation, i.e., electrostatic potentials created by infinite line sources parallel to metallic infinite cylinders of the various shapes. The solution is naturally expressed in the transformed domain, but usually a direct expression in the original (x,y) coordinates is easily obtained. In most cases, the proposed solutions are an order of magnitude simpler than those obtained by other approaches. View full abstract»

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  • Plane wave reflection and refraction involving a finitely conducting medium

    Publication Year: 2003 , Page(s): 54 - 61
    Cited by:  Papers (5)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (420 KB) |  | HTML iconHTML  

    In this work the structure of electromagnetic field in a lossy conducting medium is studied in detail. The meaning of the complex angle of refraction is explained in terms of real parameters involved in this problem. The concepts are illustrated with a wave refracting from air into pure water at a frequency of 95 GHz and an incidence angle of 60°. The approach is similar to that used to derive refraction in many electromagnetic textbooks, such as Stratton (J. A. Stratton, 1941), which has been cited in many of the textbooks published since. Our results agree with his for the real angle of the equiphase surface of the refracted fields, but we explore further subjects, including the instantaneous and time-averaged Pointing vectors. View full abstract»

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  • Optimizing backscattering from arrays of perfectly conducting strips

    Publication Year: 2003 , Page(s): 26 - 33
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (546 KB) |  | HTML iconHTML  

    Eight different numerical optimization algorithms tackled the problem of finding the best spacings for an array of perfectly conducting strips in order to get desirable backscattering characteristics. Local optimizers worked well when the problem was relatively simple and had few parameters. As the complexity of the problem increased, the genetic algorithm proved a better approach. In general, a hybrid genetic algorithm (GA) worked best, because it combined the power of the local search with a global search. This paper presents optimized results that were averaged over twenty independent runs, and discusses the pros and cons of the various approaches. View full abstract»

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  • A MATLAB experimental framework for electromagnetic education

    Publication Year: 2003 , Page(s): 86 - 90
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (468 KB)  

    An experimental framework, built in MATLAB, is presented here. Its aim is to provide an easy-to-use graphical user interface, acting as a "wrapper" for electromagnetic experimental simulation codes written by the educator. The framework is designed to relieve the coder from most of the programming burden, and to provide the students with a friendly, consistent approach to the numerical simulations. View full abstract»

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  • Measurement distance effects on Φ-symmetric shaped patterns generated by circular continuous apertures

    Publication Year: 2003 , Page(s): 68 - 70
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (261 KB)  

    Sidelobe-level and ripple behaviors of Φ-symmetric shaped patterns, generated by circular, real and complex, continuous Taylor distributions, is analyzed as a function of measurement distances. This paper reveals that real distributions suffer less-significant power pattern degradation than complex distributions at near-field distances. View full abstract»

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  • Electromagnetic analysis of beam-scanning antenna at millimeter-wave band based on photoconductivity using Fresnel-zone-plate technique

    Publication Year: 2003 , Page(s): 13 - 25
    Cited by:  Papers (4)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (722 KB) |  | HTML iconHTML  

    The proposed antenna is a Fresnel-zone-plate antenna (FZPA) in the Ka band that scans the beam of millimeter wave source. The antenna includes a semiconductor wafer (silicon, gallium arsenide) in which a spatially varying density of charge carriers is selectively established through selective optical illumination using a pulse laser. It is shown that the beam of the antenna can be scanned through the space by reconfiguring the masking of the wafer. The beam scanning is done in the transmission mode. The analysis of the far-zone radiation characteristics is presented using physical optics. Results for the antenna gain, the efficiency, and the co- and cross-polar patterns are given. View full abstract»

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  • The work of Marconi in microwave communications

    Publication Year: 2003 , Page(s): 46 - 53
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (702 KB) |  | HTML iconHTML  

    This paper describes the first land and sea microwave links realized by Guglielmo Marconi in 1932. While other researchers were experimenting with sea microwave links in the same period, Marconi's land experiment was the first successful microwave link over a roughly hilly terrain, and led to the first permanent microwave radio link. Besides the description of the experiment, many photos and figures are included, some of which are extracted from Marconi's original works. View full abstract»

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  • The bi-polar near-field antenna measuring system at Wroclaw University of Technology

    Publication Year: 2003 , Page(s): 74 - 83
    Cited by:  Papers (3)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (989 KB) |  | HTML iconHTML  

    This paper presents a near-field antenna measurement system that was developed in-house. The capabilities of our bi-polar system were extended by a backward-projection processing of data. The amplitude and phase distribution within the array elements can thus be reconstructed. Major applications of the presented near-field system are in research on advanced beamforming, and in investigations into large-scale integration of lightweight arrays. The results presented were obtained for planar microstrip arrays, and for a phased array operating between 5 GHz and 12 GHz. View full abstract»

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  • Comments on the hybrid model for propagation loss prediction in tunnels

    Publication Year: 2003 , Page(s): 156 - 158
    Cited by:  Papers (2)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (246 KB) |  | HTML iconHTML  

    The hybrid model for propagation-loss prediction in tunnels is discussed and its limitations are given. The values from the waveguide model with γ2<2 are applicable for only short distances and for tunnels with low specific attenuation factor (α). In general, γ2 can take any value higher than two. View full abstract»

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  • Study of deployed and modular active phased-array multibeam satellite antenna

    Publication Year: 2003 , Page(s): 34 - 45
    Cited by:  Papers (11)  |  Patents (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (990 KB) |  | HTML iconHTML  

    A deployed, self-cooled and modular (tile-based) active phased array for multibeam applications has recently been proposed in the literature. This novel antenna facilitates the implementation of large array antennas in space with many beams from the same aperture, offering a flexible payload with the potential for high traffic capacity. However, the configuration also raises some questions about degradation in antenna performance, due to constraints such as non-circular aperture, frame gap, uniform amplitude excitation, and a calibration boom deployed in front of the array. Methods dealing with these issues are discussed in this paper. It is shown that a phase-only optimization technique can effectively reduce interference between same-frequency spatially reused beams, and can compensate for EIRP and C/I degradation for tile-correlated errors and failures. View full abstract»

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  • Inauguration of IEEE Marconi Milestone in Salvan

    Publication Year: 2003 , Page(s): 84 - 85
    Cited by:  Papers (1)
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (355 KB) |  | HTML iconHTML  

    First Page of the Article
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  • How electromagnetically sharp is a needle?

    Publication Year: 2003 , Page(s): 118 - 122
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (247 KB)  

    The properties of a length of infinitely thin, perfectly conducting straight wire have been discussed extensively in the literature. But there remains a simple static problem, which is the distribution of a charge, q, along the length of the wire. Far from the ends, one may expect a uniform linear charge density, /spl rho//sub l/, and an electric field perpendicular to the axis. The behavior near the tips however is the real problem. View full abstract»

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  • Incorporation by reference in a patent application

    Publication Year: 2003 , Page(s): 141 - 147
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (522 KB)  

    First Page of the Article
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  • Design of wideband impedance transformers

    Publication Year: 2003 , Page(s): 71 - 72
    Save to Project icon | Request Permissions | Click to expandQuick Abstract | PDF file iconPDF (1013 KB) |  | HTML iconHTML  

    Although design methods of wideband impedance transformers are known, in some cases there can be limitations on implementation. A practical limitation is the availability of the required characteristic impedance levels, particularly in antenna array feed structures. View full abstract»

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The IEEE Antennas and Propagation Magazine covers all areas relating to antenna theory, design, and practice.

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Editor-in-Chief
Mahta Moghaddam