Mutual Coupling Effects in Unequally Spaced Linear Arrays PDF Download
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Author: Peter Paul Ilacqua
Publisher:
ISBN:
Category : Antenna arrays
Languages : en
Pages : 178
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Book Description
Author: Peter Paul Ilacqua
Publisher:
ISBN:
Category : Antenna arrays
Languages : en
Pages : 178
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Book Description
Author: Harvey K. Schuman
Publisher:
ISBN:
Category : Antenna arrays
Languages : en
Pages : 156
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Book Description
Analytical techniques presented thus far for treatment of unequally spaced antenna arrays have pointed out that desirable radiation characteristics can be achieved using only the interelement spacings as design parameters. The advantage is that the excitation amplitudes required can be either uniform or nearly uniform across the array, thereby allowing use of a simple feed system for excitation of the array elements and minimizing adverse mutual coupling effects. The design methods have found only limited applications, however, since results are not always reliable due to the approximations necessary to simplify the analytical work. Various computational methods have been presented to circumvent this problem, but these in turn suffer disadvantage in that they provide no control over the ultimate positions of the array elements, giving rise to unrealistic spacing configurations and severe realization problems through mutual coupling. In this work a new computational technique is presented for designing unequally spaced arrays. The method is particularly suitable for use with modern high-speed electronic computers, and allows certain practical restrictions or constraints to be included in the design procedure by allowing use of a limited number of different excitation amplitude levels. The result in any given example is an unequally spaced linear array designed for a specified sidelobe level, with a number of amplitude levels appropriate for insuring that prespecified spacing restrictions are met. Thus, the practical difficulties encountered with the results of other computational schemes are largely avoided. Several examples are given, and both theoretical and experimental results are included. (Author).
Author: Wasyl Wasylkiwskyj
Publisher:
ISBN:
Category :
Languages : en
Pages : 47
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Book Description
The scope of the paper is limited to a theoretical analysis of a linear semi-infinite array of uniformly spaced elements, but the analytical results thus obtained should prove of value in providing quantitative estimates of edge effects in large linear phased arrays. The analysis is sufficiently general to encompass the usual electrically small radiators commonly employed in phased arrays (viz., dipoles, slots, etc.). However, other than one example of an array of ideal elements (chosen more for its simplicity than realism) no specific numerical results have been obtained. The treatment is mathematical and the emphasis has been more on methods rather than concrete results. (Author).
Author: Bradley J. Strait
Publisher:
ISBN:
Category :
Languages : en
Pages : 67
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Book Description
Several methods for designing linear arrays of antennas are summarized. Techniques for treating both equally spaced and unequally spaced arrays are discussed, and it is shown that desirable array pattern characteristics can be designed for and realized without requiring undue complication of either the amplitude distribution or the spacing configuration. The resulting arrays are called partially uniform since considerable uniformity is provided with regard to both the excitation amplitudes and the interelement spacings in order to minimize the realization problems brought about by the adverse effects of mutual coupling. The methods presented here for equally spaced arrays apply to both broadside and endfire conditions and can be used to place pattern nulls in one or more specified directions. These methods have additional advantage in that an equivalence is established with equally spaced arrays allowing determination of the types of results that can be expected when unequal spacings are used as design parameters. Several experimental examples are given. (Author).
Author: Robert A. Gierard
Publisher:
ISBN:
Category :
Languages : en
Pages : 247
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Book Description
This computer analysis assessed the impact of mutual coupling on the side lobe performance of Chebyshev linear arrays as a function array size, scan condition, and the severity of Chebyshev taper. Array elements were horizontal parallel dipoles over a ground plane. Three simple compensation schemes to account for coupling were investigated. A fortran computer program, based upon King-Middleton's modified, zero-order, two-term theory for cylindrical dipoles, was written to calculate the generalized impedance matrix for the linear array, dipole current distributions and the far-field H-plane pattern in the presence of coupling. It is sufficiently general to allow the user of specify, number of dipoles, dipole length and radius, dipole spacing, height above ground plane, frequency, and complex generator voltages driving the array. The results relate side lobe degradation (growth) to array size, scan condition, and desired Chebyshev side lobe level. Additional programs were written to reverse the matrix solution, and solve for generator voltages, which after coupling, produce a base current distribution with a Chebyshev taper. Three simpler compensation schemes then used approximations of the compensated (complex) voltages to drive the array. Theses (rh).
Author: Hema Singh
Publisher: Springer
ISBN: 9812877908
Category : Technology & Engineering
Languages : en
Pages : 56
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Book Description
This book presents a detailed and systematic analytical treatment of scattering by an arbitrary dipole array configuration with unequal-length dipoles, different inter-element spacing and load impedance. It provides a physical interpretation of the scattering phenomena within the phased array system. The antenna radar cross section (RCS) depends on the field scattered by the antenna towards the receiver. It has two components, viz. structural RCS and antenna mode RCS. The latter component dominates the former, especially if the antenna is mounted on a low observable platform. The reduction in the scattering due to the presence of antennas on the surface is one of the concerns towards stealth technology. In order to achieve this objective, a detailed and accurate analysis of antenna mode scattering is required. In practical phased array, one cannot ignore the finite dimensions of antenna elements, coupling effect and the role of feed network while estimating the antenna RCS. This book presents the RCS estimation of an array with unequal-length dipoles. The signal reflections within the antenna system and the mutual coupling effect are considered to arrive at the total RCS for series and parallel feed. The computations are valid for any arbitrary array configurations, including side-by-side arrangement, parallel-in-echelon, etc.
Author: Trevor S. Bird
Publisher: John Wiley & Sons
ISBN: 1119564980
Category : Technology & Engineering
Languages : en
Pages : 484
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Book Description
Mutual Coupling Between Antennas A guide to mutual coupling between various types of antennas in arrays such as wires, apertures and microstrip patches or antennas co-sited on platforms Mutual Coupling Between Antennas explores the theoretical underpinnings of mutual coupling, offers an up-to-date description of the physical effects of mutual coupling for a variety of antennas, and contains techniques for analysing and assessing its effects. The book puts the topic in historical context, presents an integral equation approach, includes the current techniques, measurement methods, and discusses the most recent advances in the field. With contributions from noted experts on the topic, the book reviews practical aspects of mutual coupling and examines applications that clearly demonstrate where the performance is impacted both positively and negatively. Mutual Coupling Between Antennas contains information on how mutual coupling can be analysed with a wide range of methods from direct computer software using discrete methods, to integral equations and Greens function methods as well as approximate asymptotic methods. This important text: Provides a theoretical background for understanding mutual coupling between various types of antennas Describes the interaction that occurs between antennas, both planned and unplanned Explores a key aspect of arrays in any wireless, radar or sensing system operating at radio frequencies Offers a groundbreaking book on antenna mutual coupling Written for antenna engineers, technical specialists, researchers and students, Mutual Coupling Between Antennas is the first book to examine mutual coupling between various types of antennas including wires, horns, microstrip patches, MIMO antennas, co-sited antennas and arrays in planar or conformal configurations.
Author: Sawyer D. Campbell
Publisher: John Wiley & Sons
ISBN: 1119853915
Category : Technology & Engineering
Languages : en
Pages : 596
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Book Description
Advances in Electromagnetics Empowered by Artificial Intelligence and Deep Learning Authoritative reference on the state of the art in the field with additional coverage of important foundational concepts Advances in Electromagnetics Empowered by Artificial Intelligence and Deep Learning presents cutting-edge research advances in the rapidly growing areas in optical and RF electromagnetic device modeling, simulation, and inverse-design. The text provides a comprehensive treatment of the field on subjects ranging from fundamental theoretical principles and new technological developments to state-of-the-art device design, as well as examples encompassing a wide range of related sub-areas. The content of the book covers all-dielectric and metallodielectric optical metasurface deep learning-accelerated inverse-design, deep neural networks for inverse scattering, applications of deep learning for advanced antenna design, and other related topics. To aid in reader comprehension, each chapter contains 10-15 illustrations, including prototype photos, line graphs, and electric field plots. Contributed to by leading research groups in the field, sample topics covered in Advances in Electromagnetics Empowered by Artificial Intelligence and Deep Learning include: Optical and photonic design, including generative machine learning for photonic design and inverse design of electromagnetic systems RF and antenna design, including artificial neural networks for parametric electromagnetic modeling and optimization and analysis of uniform and non-uniform antenna arrays Inverse scattering, target classification, and other applications, including deep learning for high contrast inverse scattering of electrically large structures Advances in Electromagnetics Empowered by Artificial Intelligence and Deep Learning is a must-have resource on the topic for university faculty, graduate students, and engineers within the fields of electromagnetics, wireless communications, antenna/RF design, and photonics, as well as researchers at large defense contractors and government laboratories.
Author: Moeness G. Amin
Publisher: John Wiley & Sons
ISBN: 1394191014
Category : Technology & Engineering
Languages : en
Pages : 516
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Book Description
Specialized resource providing detailed coverage of recent advances in theory and applications of sparse arrays Sparse Arrays for Radar, Sonar, and Communications discusses various design approaches of sparse arrays, including those seeking to increase the corresponding one-dimensional and two-dimensional virtual array apertures, as well as others that configure the arrays based on solutions of constrained minimization problems. The latter includes statistical bounds and signal-to-interference and noise ratio; in this respect, the book utilizes the recent strides made in convex optimizations and machine learning for sparse array configurability in both fixed and dynamic environments. Similar ideas are presented for sparse array-waveform design. The book also discusses the role of sparse arrays in improving target detection and resolution in radar, improving channel capacity in massive MIMO, and improving underwater target localization in sonar. It covers different sparse array topologies, and provides various approaches that deliver the optimum and semi-optimum sparse array transceivers. . Edited by a world-leading expert in Radar and Signal Processing and contributed to by world-class researchers in their respective fields, Sparse Arrays for Radar, Sonar, and Communications covers topics including: Utilizing sparse arrays in emerging technologies and showing their offerings in various sensing and communications applications Applying sparse arrays to different environments and obtain superior performances over conventional uniform arrays Solving the localization, beamforming, and direction-finding problems using non-uniform array structures for narrowband and wideband signals Designing sparse array structures for both stationary and moving platforms that produce physical and synthesized array apertures. Using deep neural networks that learn the underlying complex nonlinear model and output the sparse array configuration using representations of the input data spatio-temporal observations Solving for optimum sparse array configurations and beamforming coefficients in sensing using iterative convex optimization methods Providing complete coverage of the recent considerable progress in sparse array design and configurations, Sparse Arrays for Radar, Sonar, and Communications is an essential resource on the subject for graduate students and engineers pursuing research and applications in the broad areas of active/passive sensing and communications.
Author: United States. National Bureau of Standards
Publisher:
ISBN:
Category : Radio
Languages : en
Pages : 1354
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Book Description
