Finite Antenna Arrays And Fss

A periodic surface is an assembly of identical elements arranged in a one or two-dimensional array. Such surfaces have various effects on incident electromagnetic waves. Their applications range from antennas to stealth aircraft.This book discusses finite antenna arrays and how to minimize the radar cross section of these arrays. "Ben has been the world-wide guru of this technology...Ben Munk has written a book that represents the epitomy of practical understanding." W. Bahret, United States Air Force Frequency selective surfaces (FSSs) have important military and civilian applications including antenna theory, satellite communications and stealth technology Author is an authory on the subject, having been instrumental in the development of stealth technology for the US Air Force Much of the material in this book was deemed classified due to its importance to defence

Abstract: A finite passive periodic antenna array, or Frequency Selective Surface, exhibits a phenomenon that an infinite passive array, or FSS, does not. Namely, surface waves which propagate along the periodic array structure may be induced in the array at frequencies below the resonant frequency of the array. These surface waves may radiate energy when they reach the ends or other discontinuities in the finite array and may therefore increase the Radar Cross Section of the array.

The Most Complete, Up-to-Date Coverage of the Finite Element Analysis and Modeling of Antennas and Arrays Aimed at researchers as well as practical engineers—and packed with over 200 illustrations including twenty-two color plates—Finite Element Analysis of Antennas and Arrays presents: Time- and frequency-domain formulations and mesh truncation techniques Antenna source modeling and parameter calculation Modeling of complex materials and fine geometrical details Analysis and modeling of narrowband and broadband antennas Analysis and modeling of infinite and finite phased-array antennas Analysis and modeling of antenna and platform interactions Recognizing the strengths of other numerical methods, this book goes beyond the finite element method and covers hybrid techniques that combine the finite element method with the finite difference time-domain method, the method of moments, and the high-frequency asymptotic methods to efficiently deal with a variety of complex antenna problems. Complemented with numerous examples, this cutting-edge resource fully demonstrates the power and capabilities of the finite element analysis and its many practical applications.

An in-depth treatment of array phenomena and all aspects of phased array analysis and design Phased Array Antennas, Second Edition is a comprehensive reference on the vastly evolving field of array antennas. The Second Edition continues to provide an in-depth evaluation of array phenomena with a new emphasis on developments that have occurred in the field over the past decade. The book offers the same detailed coverage of all practical and theoretical aspects of phased arrays as the first edition, but it now includes: New chapters on array-fed reflector antennas; connected arrays; and reflect arrays and retrodirective arrays Brand-new coverage of artificial magnetic conductors, and Bode matching limitations A clear explanation of the common misunderstanding of scan element pattern measurement, along with appropriate equations In-depth coverage of finite array Gibbsian models, photonic feeding and time delay, waveguide simulators, and beam orthogonality The book is complemented with a multitude of original curves and tables that illustrate how particular behaviors were derived from the author's hundreds of programs developed over the past forty years. Additionally, numerous computer design algorithms and numerical tips are included throughout the book to help aid in readers' comprehension. Phased Array Antennas, Second Edition is an ideal resource for antenna design engineers, radar engineers, PCS engineers, and communications engineers, or any professional who works to develop radar and telecommunications systems. It also serves as a valuable textbook for courses in phased array design and theory at the upper-undergraduate and graduate levels.

Abstract: Since the first radio link was built by Hertz in 1886, antennas have become a critical technology which allows people to stay connected and informed. Several advances have been made in the field of antenna theory and technology in the past hundred twenty years. Among them is the characterization of frequency selective surfaces (FSS), which are periodic arrays of passive elements or slots that act as a band stop or a band pass filters respectively to propagating electromagnetic waves. The purpose of this project was to construct an antenna which is transmissive outside of the band of operation. For example, the antenna designed in this project operates in a band of 1-2 GHz. The goal of this project is to be able to place an antenna operating at 4-8 GHz behind this antenna and have it be able to "look though" the first antenna as if it wasn't there. This will allow the user to stack antennas one behind the other and thus increase the density of antennas in a given area. This is advantageous in applications where the available real estate upon which to place antennas is limited, such as on ships and submarines. This antenna has two main components - an array of radiating elements and a reflector. The radiating array will be transmissive at 4-8 GHz as long as it does not radiate energy at this frequency and does not significantly scatter energy. These constraints are easily met by creating an array of wire elements. Reflectors, on the other hand, are commonly composed of a solid metal plate, which will reflect energy at any frequency. However, this project uses an element FSS for a reflector. As a result this reflector will only reflect energy in the stop band. Sufficiently outside of this band, it will be transmissive. While an entire antenna was designed for sake of completeness, the focus of this project was the design and testing of the FSS reflector. There were two main components to this project. The first was to use computational codes to design the antenna. Specifically, the antenna was designed using a Method of Moments (MoM) code, which calculates gain patterns for finite antennas. These results were then compared to a periodic moment method code, which calculates the ideal result for an infinite structure. This design process was completed in several steps. First the FSS array was designed to be reflective in the L band (1-2 GHz) and transmissive outside of this band. Following this the radiating array was designed to realize sufficiently flat L band bandwidth. The FSS reflector and radiating array were then combined together and the gain and transmissivity were then calculated for the entire antenna. Finally a prototype of the FSS reflector was built and tested. Time constraints prevented the construction of the entire antenna. The results of these tests are in very good agreement with each other. MoM tests show the FSS is within 1 dB of perfect reflectivity over the entire L band range. The prototype was within 2 dB of perfect reflectivity over the same range. This deviation is explained by unavoidable human error in the construction of the FSS. The periodic moment method code is also computed similar results. The bandwidth wasn't quite as large in the PMM test, but this is expected and is explained by the fact that edge diffraction on finite structures increases the bandwidth. The transmissivity of this FSS is within 2 dB of perfect transmissivity in the C band (4-8 GHz.) Finally the gain of the radiating array has a 2 dB variation over L and, and the gain of the entire antenna has a 3 dB variation over L band.

The Most Complete, Up-to-Date Coverage of the Finite Element Analysis and Modeling of Antennas and Arrays Aimed at researchers as well as practical engineers—and packed with over 200 illustrations including twenty-two color plates—Finite Element Analysis of Antennas and Arrays presents: Time- and frequency-domain formulations and mesh truncation techniques Antenna source modeling and parameter calculation Modeling of complex materials and fine geometrical details Analysis and modeling of narrowband and broadband antennas Analysis and modeling of infinite and finite phased-array antennas Analysis and modeling of antenna and platform interactions Recognizing the strengths of other numerical methods, this book goes beyond the finite element method and covers hybrid techniques that combine the finite element method with the finite difference time-domain method, the method of moments, and the high-frequency asymptotic methods to efficiently deal with a variety of complex antenna problems. Complemented with numerous examples, this cutting-edge resource fully demonstrates the power and capabilities of the finite element analysis and its many practical applications.

A Convincing and Controversial Alternative Explanation of Metamaterials with a Negative Index of Refraction In a book that will generate both support and controversy, one of the world's foremost authorities on periodic structures addresses several of the current fashions in antenna design—most specifically, the popular subject of double negative metamaterials. Professor Munk provides a comprehensive theoretical electromagnetic investigation of the issues and concludes that many of the phenomena claimed by researchers may be impossible. While denying the existence of negative refraction, the author provides convincing alternative explanations for some of the experimental examples in the literature. Although the debate on this subject is just beginning, Professor Munk has received support by various numerical simulations, winning him the encouragement of numerous experts in the field. The issues that are raised here have not been addressed thoroughly by the metamaterials community, and this book will serve as a catalyst for much healthy debate and discussion. Metamaterials: Critique and Alternatives is destined to become a classic resource for graduate students and researchers in electromagnetics, antenna theory, materials research, and chemistry.

"...Ben has been the world-wide guru of this technology, providing support to applications of all types. His genius lies in handling the extremely complex mathematics, while at the same time seeing the practical matters involved in applying the results. As this book clearly shows, Ben is able to relate to novices interested in using frequency selective surfaces and to explain technical details in an understandable way, liberally spiced with his special brand of humor... Ben Munk has written a book that represents the epitome of practical understanding of Frequency Selective Surfaces. He deserves all honors that might befall him for this achievement." -William F. Bahret. Mr. W. Bahret was with the United States Air Force but is now retired. From the early 50s he sponsored numerous projects concerning Radar Cross Section of airborne platforms in particular antennas and absorbers. Under his leadership grew many of the concepts used extensively today, as for example the metallic radome. In fact, he is by many considered to be the father of stealth technology. "This book compiles under one cover most of Munk's research over the past three decades. It is woven with the physical insight that he has gained and further developed as his career has grown. Ben uses mathematics to whatever extent is needed, and only as needed. This material is written so that it should be useful to engineers with a background in electromagnetics. I strongly recommend this book to any engineer with any interest in phased arrays and/or frequency selective surfaces. The physical insight that may be gained from this book will enhance their ability to treat additional array problems of their own." -Leon Peters, Jr. Professor Leon Peters, Jr., was a professor at the Ohio State University but is now retired. From the early sixties he worked on, among many other things, RCS problems involving antennas and absorbers. This book presents the complete derivation of the Periodic Method of Moments, which enables the reader to calculate quickly and efficiently the transmission and reflection properties of multi-layered Frequency Selective Surfaces comprised of either wire and/or slot elements of arbitrary shape and located in a stratified medium. However, it also gives the reader the tools to analyze multi-layered FSS's leading to specific designs of the very important Hybrid Radome, which is characterized by constant band width with angle of incidence and polarization. Further, it investigates in great detail bandstop filters with large as well as narrow bandwidth (dichroic surfaces). It also discusses for the first time, lossy elements used in producing Circuit Analog absorbers. Finally, the last chapter deals with power breakdown of FSS's when exposed to pulsed signals with high peak power. The approach followed by most other presentations simply consists of expanding the fields around the FSS, matching the boundary conditions and writing a computer program. While this enables the user to obtain calculated results, it gives very little physical insight and no help in how to design actual multi-layered FSS's. In contrast, the approach used in this title analyzes all curves of desired shapes. In particular, it discusses in great detail how to produce radomes made of FSS's located in a stratified medium (Hybrid Radomes), with constant band width for all angles of incidence and polarizations. Numerous examples are given of great practical interest. More specifically, Chapter 7 deals with the theory and design of bandpass radomes with constant bandwidth and flat tops. Examples are given for mono-, bi- and tri-planar designs. Chapter 8 deals with bandstop filters with broad as well as narrow bandwidth. Chapter 9 deals with multi-layered FSS of lossy elements, namely the so-called Circuit Analog Absorbers, designed to yield outstanding absorption with more than a decade of bandwidth. Features material previously labeled as classified by the United States Air Force.

This book provides a brief overview of the popular Finite Element Method (FEM) and its hybrid versions for electromagnetics with applications to radar scattering, antennas and arrays, guided structures, microwave components, frequency selective surfaces, periodic media, and RF materials characterizations and related topics. It starts by presenting concepts based on Hilbert and Sobolev spaces as well as Curl and Divergence spaces for generating matrices, useful in all engineering simulation methods. It then proceeds to present applications of the finite element and finite element-boundary integral methods for scattering and radiation. Applications to periodic media, metamaterials and bandgap structures are also included. The hybrid volume integral equation method for high contrast dielectrics and is presented for the first time. Another unique feature of the book is the inclusion of design optimization techniques and their integration within commercial numerical analysis packages for shape and material design. To aid the reader with the method's utility, an entire chapter is devoted to two-dimensional problems. The book can be considered as an update on the latest developments since the publication of our earlier book (Finite Element Method for Electromagnetics, IEEE Press, 1998). The latter is certainly complementary companion to this one.