Analysis of Arbitrarily Oriented Thin Wire Antenna Arrays Over Imperfect Ground Planes


Book Description

The work considers the analysis of antenna and arrays of thin wires of arbitrary orientation above imperfectly conducting ground planes. Emphasis is placed on the development of fast and accurate techniques for computation of the characteristics of antenna systems. An important problem is the evaluation of certain semi-infinite integrals encountered in the exact Sommerfeld solution. The time required for computation of these integrals is reduced by the application of interpolatory quadrature formulas. Where applicable, a modified method of steepest descent is used to evaluate the integrals. The approximate reflection coefficient method is derived from the Sommerfeld formulation via the method of steepest descent. The accuracy of the reflection coefficient method relative to the Sommerfeld method is discussed. Finally, formulas convenient for the optimization of various performance indices are discussed. Typical indices that have been optimized, both with and without constraints, are directivity, power gain, quality factor, and main beam radiation efficiency.




Analysis of Radiation by Wire Antennas Over Imperfect Ground


Book Description

Three user-oriented computer programs are presented and described for analyzing radiation from arrays of parallel vertical wires, parallel horizontal wires, and also arbitrary wire configurations over the surface of an imperfectly conducting earth. The first two programs are equipped to treat unequally spaced arrays of wires that can be of different lengths and radii and of arbitrary excitation and loading. The effects of the imperfectly conducting earth are accounted for in an essentailly exact manner by using the Sommerfeld formulation. The third program treats arbitrary wire antennas and incorporates the ground effects approximately by using the reflection-coefficient method. Computed output consists of current distribution, input impedances, and field patterns specified by the user.







BULLETIN TOME LXXIX


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TABLE DES MATIERES 1. D. Olevie, D. Djurovie — Contribution to the statistical analysis of Kirkwood's gaps 1 2. M. M. Marjanovie — Converting a directed set into a metric space 9 3. M. D. Leko — The condition of existence of twodimensional spaces geodesics of which may be represented by a linear equation 17 4. S. Aljan'eie — Regularly varying functions in asymptotic mercerian theorems 23 5. A. Torgas'ev — On infinite graphs with five non-zero eigenvalues 31 Ово дело је лиценцирано под условима лиценце Creative Commons - Attribution-Noncommercial-No Derivative Works 3.0 Serbia http://creativecommons.org/licenses/by-nc-nd/3.0/rs/deed.en




Radio Science


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Physics of Multiantenna Systems and Broadband Processing


Book Description

An analysis of the physics of multiantenna systems Multiple-Input Multiple-Output (MIMO) technology is one of the current hot topics in emerging wireless technologies. This book fills the important need for an authoritative reference on the merits of MIMO systems based on physics and provides a sound theoretical basis for its practical implementation. The book also addresses the important issues related to broadband adaptive processing. Written by three internationally known researchers, Physics of Multiantenna Systems and Broadband Processing: Provides a thorough discussion of the physical and mathematical principles involved in MIMO and adaptive systems Examines the electromagnetic framework of wireless communications systems Uses Maxwell's theory to provide a system-based framework for the abstract concept of channel capacity Performs various numerical simulations to observe how a typical system will behave in practice Provides a mathematical formulation for broadband adaptive processing and direction-of-arrival estimation using real antenna arrays Integrates signal processing and electromagnetics to address the performance of realistic multiantenna systems With Physics of Multiantenna Systems and Broadband Processing, communication systems engineers, graduate students, researchers, and developers will gain a thorough, scientific understanding of this important new technology.




The Physics and Mathematics of Electromagnetic Wave Propagation in Cellular Wireless Communication


Book Description

An important resource that examines the physical aspects of wireless communications based on mathematical and physical evidence The Physics and Mathematics of Electromagnetic Wave Propagation in Cellular Wireless Communicationdescribes the electromagnetic principles for designing a cellular wireless system and includes the subtle electromagnetic principles that are often overlooked in designing such a system. This important text explores both the physics and mathematical concepts used in deploying antennas for transmission and reception of electromagnetic signals and examines how to select the proper methodology from a wide range of scenarios. In this much-needed guide, the authors—noted experts in the field—explore the principle of electromagnetics as developed through the Maxwellian principles and describe the properties of an antenna in the frequency domain. The text also includes a review of the characterization of propagation path loss in a cellular wireless environment and examines ultrawideband antennas and the mechanisms of broadband transmission of both power and information. This important resource: Includes a discussion of the shortcomings of a MIMO system from both theoretical and practical aspects Demonstrates how to deploy base station antennas with better efficiency Validates the principle and the theoretical analysis of electromagnetic propagation in cellular wireless communication Contains results of experiments that are solidly grounded in mathematics and physics Written for engineers, researchers, and educators who are or plan to work in the field, The Physics and Mathematics of Electromagnetic Wave Propagation in Cellular Wireless Communicationoffers an essential resource for understanding the principles underpinning wireless communications.




Boundary Elements and Other Mesh Reduction Methods XXX


Book Description

The major motivation behind the Boundary Element Method (BEM) was to reduce the dependency of analysis on the definition of meshes. This has allowed the method to expand naturally into new techniques such as Dual Reciprocity and all other Mesh reduction Methods (MRM). MRM and BEM continue to be very active areas of research with many of the resulting techniques applied to solve increasingly complex problems. This book contains papers presented at the much-acclaimed thirtieth International Conference on Boundary Elements and other Mesh Reductions Methods . The proceedings contain papers on practically all major developments in Boundary Elements, including the most recent MRM techniques, grouped under the following topics: Fluid Flow; Heat Transfer; Electrical Engineering and Electromagnetics; Damage Mechanics and Fracture; Mesh Reduction Techniques; Advanced Computational Techniques




R & D Abstracts


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