A Review of Optimisation Techniques for Layered Radar Absorbing Materials, Including the Genetic Algorithm PDF Download
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Category :
Languages : en
Pages : 23
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The ability of a material to absorb radar waves (microwave radiation) depends on the permittivity & permeability of the material and its structure. A multilayer structure of alternating resistive sheets & low dielectric spacers has been found to make an effective radar absorber if the layers are spaced a quarter wavelength apart and the resistance of the sheets has specific values. To make a multilayer absorber with the widest possible bandwidth, it is necessary to use an optimization technique due to the complexity of the equations describing the reflectivity from an absorber. This paper reviews optimal design techniques for multilayer microwave absorbers. These methods include analytical approximations, gradient optimization routines, simulated annealing, and the genetic algorithm. Particular attention is paid to the genetic algorithm, a highly parallel stochastic technique that permits multi-objective optimization and has a high probability of finding the global minimum.
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Category :
Languages : en
Pages : 23
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Book Description
The ability of a material to absorb radar waves (microwave radiation) depends on the permittivity & permeability of the material and its structure. A multilayer structure of alternating resistive sheets & low dielectric spacers has been found to make an effective radar absorber if the layers are spaced a quarter wavelength apart and the resistance of the sheets has specific values. To make a multilayer absorber with the widest possible bandwidth, it is necessary to use an optimization technique due to the complexity of the equations describing the reflectivity from an absorber. This paper reviews optimal design techniques for multilayer microwave absorbers. These methods include analytical approximations, gradient optimization routines, simulated annealing, and the genetic algorithm. Particular attention is paid to the genetic algorithm, a highly parallel stochastic technique that permits multi-objective optimization and has a high probability of finding the global minimum.
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Category :
Languages : en
Pages : 38
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Book Description
The absorption of microwaves by a material depends on the properties of the material and its structure. Broadband absorbers can be fabricated by stacking resistive sheets separated by low dielectric spacers with a thickness of a quarter wavelength. This type of multilayered resonant absorber is called the Jaumann absorber. In this paper optimal design techniques for multilayer microwave absorbers are reviewed. These methods include analytical approximations, gradient optimisation routines, simulated annealing and the genetic algorithm. The genetic algorithm is a highly parallel stochastic technique that permits multi-objective optimisation and has a high probability of finding the global minimum.
Author: Vineetha Joy
Publisher: CRC Press
ISBN: 1000409058
Category : Technology & Engineering
Languages : en
Pages : 64
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Book Description
Stealth technology is a crucial pre-requisite in the combat zone, where swiftness, surprise and initiative are the decisive elements for survivability. The supreme goal here is to reduce the visibility of military vehicles by shaping, application of radar absorbing materials, passive cancellation, active cancellation etc. With respect to multilayered radar absorbing structures (RAS), this book presents an efficient algorithm based on particle swarm optimization (PSO), for the material selection as well as optimization of thickness of multilayered RAS models considering both normal as well as oblique incidence cases. It includes a thorough overview of the theoretical background required for the analysis of multilayered RAS as well as the step-by-step procedure for the implementation of PSO-based algorithm. The accuracy and computational efficiency of the indigenously developed code is also clearly established using relevant validations and case studies. FEATURES Provides step-by-step procedure for the implementation of particle swarm optimization (PSO) based algorithm in the context of multilayered radar absorbing structures (RAS) design Helps to understand the EM design, analysis and optimization of multilayered RAS Describes the theoretical background required for the analysis of multilayered RAS Illustrates in detail the theoretical formulation supported by intuitive ray diagrams and comprehensive flowcharts to implement the algorithm with ease Includes elaborate validations and case studies This book will serve as a valuable resource for students, researchers, scientists, and engineers involved in the electromagnetic design and development of multi-layered radar absorbing structures.
Author: National Aeronautics and Space Administration (NASA)
Publisher:
ISBN: 9781726156608
Category :
Languages : en
Pages : 36
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Book Description
A novel, real-valued Genetic Algorithm (GA) was designed and implemented to minimize the reflectivity and/or transmissivity of an arbitrary number of homogeneous, lossy dielectric or magnetic layers of arbitrary thickness positioned at either the center of an infinitely long rectangular waveguide, or adjacent to the perfectly conducting backplate of a semi-infinite, shorted-out rectangular waveguide. Evolutionary processes extract the optimal physioelectric constants falling within specified constraints which minimize reflection and/or transmission over the frequency band of interest. This GA extracted the unphysical dielectric and magnetic constants of three layers of fictitious material placed adjacent to the conducting backplate of a shorted-out waveguide such that the reflectivity of the configuration was 55 dB or less over the entire X-band. Examples of the optimization of realistic multi-layer absorbers are also presented. Although typical Genetic Algorithms require populations of many thousands in order to function properly and obtain correct results, verified correct results were obtained for all test cases using this GA with a population of only four.Hall, John MichaelLangley Research CenterGENETIC ALGORITHMS; ARTIFICIAL INTELLIGENCE; ANTIRADAR COATINGS; DIELECTRICS; RECTANGULAR WAVEGUIDES; TRANSMISSIVITY; REFLECTANCE; CHROMOSOMES; BOUNDARY CONDITIONS; FINITE VOLUME METHOD; METHOD OF MOMENTS; SUPERHIGH FREQUENCIES; MAGNETIC PERMEABILITY; MULTILAYER INSULATION; INSULATION...
Author: Angsuman Sarkar
Publisher: CRC Press
ISBN: 1000565394
Category : Science
Languages : en
Pages : 377
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Book Description
Providing cutting-edge research on nanoelectronics and photonic devices and its application in future integrated circuits, this state-of-the-art book tackles the challenges of the different detailed theoretical and analytical models of solving the problems of various nanodevices. The volume also explores from different angles the roles of material composition and choice of materials that now play the most critical role in determining outcomes of low-dimensional nanoelectronic devices. The applications of those findings are extremely beneficial for the computing and telecommunication industries. Beginning with a solid theoretical background for every chapter, this volume covers the hottest areas of present-day electronic engineering. The continuous miniaturization of devices, components, and systems requires corresponding cutting-edge theoretical analysis supported by simulated findings before actual fabrication. That purpose is given maximum focus in this volume, which has interdisciplinary appeal, making it a comprehensive technological volume that deals with underlying aspects of physics, materials, structures in nano-regime, and the corresponding end-product in the form of devices.
Author:
Publisher:
ISBN:
Category : Microelectronics
Languages : en
Pages : 410
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Book Description
Author: Randy L. Haupt
Publisher: John Wiley & Sons
ISBN: 0470106271
Category : Science
Languages : en
Pages : 317
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Book Description
A thorough and insightful introduction to using genetic algorithms to optimize electromagnetic systems Genetic Algorithms in Electromagnetics focuses on optimizing the objective function when a computer algorithm, analytical model, or experimental result describes the performance of an electromagnetic system. It offers expert guidance to optimizing electromagnetic systems using genetic algorithms (GA), which have proven to be tenacious in finding optimal results where traditional techniques fail. Genetic Algorithms in Electromagnetics begins with an introduction to optimization and several commonly used numerical optimization routines, and goes on to feature: Introductions to GA in both binary and continuous variable forms, complete with examples of MATLAB(r) commands Two step-by-step examples of optimizing antenna arrays as well as a comprehensive overview of applications of GA to antenna array design problems Coverage of GA as an adaptive algorithm, including adaptive and smart arrays as well as adaptive reflectors and crossed dipoles Explanations of the optimization of several different wire antennas, starting with the famous "crooked monopole" How to optimize horn, reflector, and microstrip patch antennas, which require significantly more computing power than wire antennas Coverage of GA optimization of scattering, including scattering from frequency selective surfaces and electromagnetic band gap materials Ideas on operator and parameter selection for a GA Detailed explanations of particle swarm optimization and multiple objective optimization An appendix of MATLAB code for experimentation
Author: Anyong Qing
Publisher: Springer Science & Business Media
ISBN: 3642128696
Category : Technology & Engineering
Languages : en
Pages : 225
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Book Description
Differential evolution has proven itself a very simple while very powerful stochastic global optimizer. It has been applied to solve problems in many scientific and engineering fields. This book focuses on applications of differential evolution in electromagnetics to showcase its achievement and capability in solving synthesis and design problems in electromagnetics.Topics covered in this book include:• A comprehensive up-to-date literature survey on differential evolution• A systematic description of differential evolution• A topical review on applications of differential evolution in electromagnetics• Five new application examplesThis book is ideal for electromagnetic researchers and people in differential evolution community. It is also a valuable reference book for researchers and students in the optimization or electrical and electronic engineering field. In addition, managers and engineers in relevant fields will find it a helpful introductory guide.
Author: Mitsuo Gen
Publisher: John Wiley & Sons
ISBN: 9780471127413
Category : Technology & Engineering
Languages : en
Pages : 436
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Book Description
The last few years have seen important advances in the use ofgenetic algorithms to address challenging optimization problems inindustrial engineering. Genetic Algorithms and Engineering Designis the only book to cover the most recent technologies and theirapplication to manufacturing, presenting a comprehensive and fullyup-to-date treatment of genetic algorithms in industrialengineering and operations research. Beginning with a tutorial on genetic algorithm fundamentals andtheir use in solving constrained and combinatorial optimizationproblems, the book applies these techniques to problems in specificareas--sequencing, scheduling and production plans, transportationand vehicle routing, facility layout, location-allocation, andmore. Each topic features a clearly written problem description,mathematical model, and summary of conventional heuristicalgorithms. All algorithms are explained in intuitive, rather thanhighly-technical, language and are reinforced with illustrativefigures and numerical examples. Written by two internationally acknowledged experts in the field,Genetic Algorithms and Engineering Design features originalmaterial on the foundation and application of genetic algorithms,and also standardizes the terms and symbols used in othersources--making this complex subject truly accessible to thebeginner as well as to the more advanced reader. Ideal for both self-study and classroom use, this self-containedreference provides indispensable state-of-the-art guidance toprofessionals and students working in industrial engineering,management science, operations research, computer science, andartificial intelligence. The only comprehensive, state-of-the-arttreatment available on the use of genetic algorithms in industrialengineering and operations research . . . Written by internationally recognized experts in the field ofgenetic algorithms and artificial intelligence, Genetic Algorithmsand Engineering Design provides total coverage of currenttechnologies and their application to manufacturing systems.Incorporating original material on the foundation and applicationof genetic algorithms, this unique resource also standardizes theterms and symbols used in other sources--making this complexsubject truly accessible to students as well as experiencedprofessionals. Designed for clarity and ease of use, thisself-contained reference: * Provides a comprehensive survey of selection strategies, penaltytechniques, and genetic operators used for constrained andcombinatorial optimization problems * Shows how to use genetic algorithms to make production schedules,solve facility/location problems, make transportation/vehiclerouting plans, enhance system reliability, and much more * Contains detailed numerical examples, plus more than 160auxiliary figures to make solution procedures transparent andunderstandable
Author:
Publisher:
ISBN:
Category : Aeronautics
Languages : en
Pages : 1016
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