Antennas: Fundamentals, design, measurement
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This is a professional level, introductory text on antenna principles, design, analysis, and measurements. It is especially suitable for persons who wish to improve their knowledge of antenna principles, concept design, performance analyses, and measurements. It is not a cookbooklike catalog for antenna design, nor does its understanding require a familiarity with electromagnetic theory, sophisticated mathematics, or complex computer techniques. The 3rd Edition updates and expands the original text by Lamont Blake, which was prepared at the undergraduate engineering, science, or technology level. For providing technical depth at the senior and graduate university levels, additions to the original book include a greatly expanded Chapter 7 on Antennas with Special Properties, a brand new Chapter 8 on Electronically Steered Arrays, and a revised Chapter 9 on Measurements. Also new to this edition are numerous appendices to the updated text and a CDROM with sample computer analyses. Reader knowledge assumes familiarity with basic college physics and mathematics. Computer computations use Mathcad® software, which can be read and used by persons without prior computer programming knowledge. The book is therefore suitable for entrylevel as well as the more experienced professionals who desire to expand their understanding of and capabilities for antenna principles, analyses, measurements, and design.
Other keywords: computer programming; universitylevel antenna textbooks; antenna measurement; submillimeter wavelengths; antenna fundamentals; antenna radiation; electromagnetic theory; sophisticated mathematics; formal course textbook; very low radio frequencies; professional training; antenna design
 Book DOI: 10.1049/SBEW040E
 ISBN: 9781891121784
 eISBN: 9781613531044
 Format: PDF

Front Matter
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1 Electromagnetic Waves
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This chapter covers the following topics: characteristics of electromagnetic waves; radiowave optical principles; radiation and reception; and environmental wavepropagation effects.
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2 Transmission Lines
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This chapter discusses transmission lines. Transmission lines must be addressed in the study of antennas for three reasons: (1) A transmission line virtually always connects an antenna to a transmitter or receiver, and is often regarded as a part of the antenna system; (2) in some types of antennas transmissionline elements are integral parts of the antenna; and (3) the principles of transmission lines are applicable to understanding some aspects of antenna theory. The material of this chapter, like that of chapter 1, is intended for review and reference. A complete treatise on transmission lines would provide material for an entire book. Therefore only the basic aspects of the subject will be covered here, with emphasis on antenna applications.
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3 Antenna Parameters
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This book is primarily concerned with the electromagnetic design and performance of antennas. Often of almost equal practical importance are the mechanical design factors, some of which will be mentioned throughout the book in connection with related discussions of electromagnetic behavior. It is desirable, however, for the reader to have some general feeling for the structural factors in the design of antennas, as an aid in relating the somewhat abstruse electromagnetic concepts to real physical structures. A thumbnail sketch of some of these aspects of antenna design will be given here, before the definition of electromagnetic parameters is taken up.
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4 Basic Radiators and Feed Methods
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The preceding chapters have been largely groundwork, covering principles, concepts, and terminology, as well as some basic antenna theory. It is now possible to discuss specific antennas.
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5 Arrays
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This chapter discusses array antennas that are designed so that the major lobe (the main beam) is pointed in one fixed direction or more. Commonly, array antennas are also designed to electronically, and thus almost instantly, change beam pointing direction. Such a beam pointing antenna is called a phased array, electronic scanning array, or electronically steered array (ESA). The general principles of arrays are discussed in the present chapter, and chapter 8, titled Electronically Steered Arrays, focuses on concepts and techniques more directly applicable to electronic beam steering.
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6 Reflectors and Lenses
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An array antenna can be used to achieve a directional radiation pattern in which the radiated power is concentrated in a beam. This paper treats an entirely different method of achieving essentially the same result, by the use of reflectors and lenses. Antennas using these devices achieve a directional effect most readily explained in terms of optical principles described in sec.
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7 Antennas with Special Properties
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Chapter 7 discusses properties of antennas and antenna analysis techniques not addressed in other chapters. Antennas are used in many different applications, and consequently there are numerous special properties needed to satisfy their requirements. The range of topics addressed in this chapter is wide, and includes techniques for providing wide bandwidths, multiple polarizations, low receiver noise, and extremely low side lobes. A specific application may, of course, employ more than one of these techniques. There is also a section solely on antennas for direction finding and another on antennas that accomplish beam scanning mechanically. The concept of syntheticaperture antennas, although perhaps more of a signal processing than an antenna topic, is also discussed here, because it is a uniquely effective way of attaining very narrow antenna beamwidths through use of a relatively small antenna on a moving platform. Finally, the chapter closes with a section on seemingly unrelated subjects, namely, geometrical theory of diffraction (GTD), method of moments (MoM), and fractals. These topics are, however, connected by the subject of radiation from sharp edges (curvatures small compared to a wavelength), which currently cannot be analyzed by exact theoretical methods.
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8 Electronically Steered Arrays
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This chapter discusses electronically steered arrays (ESAs), also commonly called phased arrays. These antennas have beams that can be electronically steered in pointing direction or beam shape, without mechanical motion, and accomplished in microseconds. Although the operation of all arrays depends on the proper phasing of the individual array elements, the terms ESA and phased array have by usage come to mean an array in which the beam is steered in direction and shape by varying the phasing of the elements. Present day ESA (or phased array) technology includes adaptive beam forming (ABF), which merges rapid beam pointing and shaping with digital signal processing separately. With ABF arrays, the phasing and time delaying of the signals from individual elements are jointly adaptively adjusted and then summed to rapidly beam point, beam shape, and Doppler filter desired received signals. In this way, the received signal output, from the summed individual array signals, may be optimized, simultaneously, for both the strength of the desired signal relative to thermal noise and relative to interference from undesired signals.
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9 Antenna Measurements
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The majority of antenna measurements lie within two basic categories: impedance measurements and pattern measurements. The first category deals with one of the most important antenna parametersthe input impedance. The second category is a very broad and equally important one, with many subcategories, such as measurements of beamwidth, minor lobe level, gain, and polarization characteristics. Measurements of efficiency and noise may also be desired in some instances. As discussed in sec. 7.8, the antenna may affect the noise level of a receiving system in special cases. Consequently, the technique of antenna noise measurements is especially important in the lower atmospheric noise region of about 1 to 10 GHz. Therefore, the basic technique of antenna noise measurement and the effect of antenna noise on overall receiving system noise are described in the present chapter.
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Appendix A: Maxwell's Equations
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James Clerk Maxwell (18311879) is generally regarded the founder of electromagnetic theory, which he conceived in 1864 (Herrera 1991). His theory began with equations that described all previously known results on both electric and magnetic experiment and theory. From those equations he removed a mathematical inconsistency by adding a term to include a then unknown electrical phenomenon, called displacement current. Displacement current flows even in a perfect dielectric. Consequently, his completed equations contain both the previously known conduction current and the upuntilthen unheard of displacement current. Electromagnetic (EM) wave propagation requires the presence of displacement current, a concept invented by Maxwell.
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Appendix B: Polarization Theory
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The most general form of a wave polarization is elliptical. The Bvector of an elliptically polarized wave can be regarded from three viewpoints. Namely, it can be considered to be (1) a rotating vector, the end point of which traces out an elliptical helix whose axis lies in the direction of propagation; (2) the resultant of the Bvectors of two linearly polarized waves of the same frequency; or (3) the resultant of the oppositely rotating Bvectors of two circularly polarized waves of the same frequency. Figure B1 illustrates the Bvector of an elliptically polarized wave at various positions in space, at a fixed instant of time. An ellipse within an xy plane is shown at the left end of this spiraling wave. The ellipse is created by tracing the endpoint (terminus) of the Bvector onto the xy plane, during the duration of one rf cycle.
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Appendix C: Review of ComplexVariable Algebra
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This part reviews complexvariable algebra.
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Appendix D: Complex Reflection Coefficients and Multipath Effects
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Chapter 1 (sec. 1.4.5) includes an introduction to the polarization dependencies of the reflection coefficient for a smooth, flat surface and to the effects of multipath propagation. The present appendix includes equations and example calculations for reflection coefficients of smooth and rough earth surfaces. Furthermore, equations are given for calculating the pattern propagation factor F for both flat earth and spherical earth geometries. In addition, the SM that accompanies this book provides examples using Mathcad for calculating reflection coefficients and the pattern propagation factor F. Therefore, by changing the initial assumptions, the user may readily attain computer calculated solutions to a wide variety of problems involving reflections applicable to either flat earth or spherical earth geometries.
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Appendix E: Radomes
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A radome is a dielectric structure that is used to protect an antenna from its environment (wind, rain, ice, salt spray, dust, insects), and it may be used to reduce aerodynamic drag. Radomes serve as feed covers, covers attached to the antenna, or covers within which an antenna moves. Therefore, they have a wide variety of shapes and wall structures (Huddleston and Bassett 1993).
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Appendix F: FarZone RangeApproximation and Phase Error
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This book section discusses the farfield region, that is, the far zone, the region of an antenna field where the antenna radiation pattern is essentially independent of the distance from the antenna.
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Appendix G: Radiating Near and Far Fields, and the Obliquity Factor
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Appendix G discusses the radiating E and Hfields that surround an energized antenna, including radiation patterns versus separation distance from an antenna aperture. This material is supplemented by the accompanying website that contains example calculations using Mathcad for radiating near and farfield patterns, where the HuygensKirchhoff formulation is used for the nearaperture radiating field calculations (Good 1990).
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Appendix H: Path Length Differences from a Planar Aperture
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Appendix H includes calculations on the differences in distances from points on a planar surface to a distant point P. The results are used in Appendix G for determining antenna patterns versus range.
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Appendix I: Effects of Random Aperture Phase Errors
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In arrays, aperture phase errors are caused by element misalignment and improper phase excitation, and surface errors are a major source of aperture error for reflector antennas. Section 6.5 includes a general discussion on reflector errors, and the present appendix addresses relatively simple calculations on the effects of random phase errors.
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Back Matter
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Supplementary material

Supplementary Files for "Antennas: Fundamentals, Design, Measurement, 3rd edition"

Mathcad and Matlab supplementary material (SM) files relating to this book can be downloaded by clicking on the icons below. Within the text of the book you will find references to the specific SM sections that relate to the material being covered. A computer icon is used in the margin to further identify sections that refer to the SM.
SM 1.0 Reflection Coefficients for Flat, Smooth Surfaces
SM 1.1. Reflection CoefficientsFlat, Smooth Sea
SM 1.2. Reflection CoefficientsFlat, Smooth Land
SM 2.0 Spherical Earth Geometry
SM 3.0 Earth Effects on Patterns and Multipath Propagation
SM 3.1. Ground Effects on Elevation Patterns
SM 3.2. Pattern Range Illumination Versus Observation Height
SM 3.3. Multipath Versus Range, Flat Conducting Surface
SM 3.4. Multipath Versus Range, Rough Flat Land
SM 3.5. Multipath Versus Range, Spherical Earth
SM 3.6. Divergence Factor Comparisons
SM 4.0 Antenna Radiation Analyses
SM 4.1. Radiating Near and Far Fields, Uniform Aperture Approximation
SM 4.2. Relative Gain Versus Range
SM 4.3. Random Aperture Phase Errors
SM 4.4. Radiating Near and Far Field Patterns of an Array
SM 4.5. Radiating Near Field along an Aperture
SM 4.6. Linear Array Pattern, Quadratic Phase Distribution
SM 4.7. Steered Array Patterns Versus Phase
SM 4.8. Steered Array Patterns at Two Frequencies
SM 4.9. Pattern of Parabolic Cylinder with Offset Feed
SM 5.0 ThreeDimensional Pattern Construction, by Aaron Loggins


Instructor Resources for "Antennas: Fundamentals, Design, Measurement, 3rd edition"

Instructor resources, including slides and solutions to exercises in the book are available for instructors who have adopted the book for a course.
To request an Instructor Pack, please email books@theiet.org, including details of your institution and the course you are teaching.
