Conformal Array Antenna Theory and Design (IEEE Press Series on Electromagnetic Wave Theory) - Hardcover

Joseffsson, Lars; Persson, Patrick

Hardcover

ISBN 10: 0471465844 ISBN 13: 9780471465843

Verlag: Wiley & Sons, 2006

Inhaltsangabe

This publication is the first comprehensive treatment of conformal antenna arrays from an engineering perspective. There are journal and conference papers that treat the field of conformal antenna arrays, but they are typically theoretical in nature. While providing a thorough foundation in theory, the authors of this publication provide readers with a wealth of hands-on instruction for practical analysis and design of conformal antenna arrays. Thus, readers gain the knowledge they need, alongside the practical know-how to design antennas that are integrated into structures such as an aircraft or a skyscraper.
 
Compared to planar arrays, conformal antennas, which are designed to mold to curved and irregularly shaped surfaces, introduce a new set of problems and challenges. To meet these challenges, the authors provide readers with a thorough understanding of the nature of these antennas and their properties. Then, they set forth the different methods that must be mastered to effectively handle conformal antennas.
 
This publication goes well beyond some of the common issues dealt with in conformal antenna array design into areas that include:
* Mutual coupling among radiating elements and its effect on the conformal antenna array characteristics
* Doubly curved surfaces and dielectric covered surfaces that are handled with a high frequency method
* Explicit formulas for geodesics on surfaces that are more general than the canonical circular cylinder and sphere
 
With specific examples of conformal antenna designs, accompanied by detailed illustrations and photographs, this is a must-have reference for engineers involved in the design and development of conformal antenna arrays. The publication also serves as a text for graduate courses in advanced antennas and antenna systems.

Über diesen Titel

Über die Autorin bzw. den Autor

Lars Josefsson is a Fulbright scholar who has been with Ericsson Microwave Systems in Sweden since 1963 when he worked on ground scattering problems associated with radar design, infrared radiation and propagation, and airborne pulse doppler radar system analysis. In 1968 he moved to the Antenna Department at Ericsson where he was involved with broadband polarizers and twist reflectors, stripline and waveguide slot arrays, and phased array antenna systems. He is responsible for the introduction of new antenna technology and systems, internal R& D projects, and internal courses relating to antennas. In 2001 he was appointed Senior Expert, Antenna Systems.
He has at the early project definition phase undertaken studies for many of the antenna systems that have later been put into production by Ericsson. These studies include, for example, dual frequency Cassegrain antennas, Flat plate antennas, Phase steered AEW antennas, and 3D Radar antennas. Dr. Josefsson has taken an active role in the AIMT project (Antenna Integrated Microwave Technology) sponsored by FMV, the Swedish Defense Material Administration. His responsibilities have included the development of mutual coupling models for certain classes of array antennas. He was technical leader for the initial development phase of Ericsson's AESA phased array radar antenna, aimed at next generation airborne radar applications. Currently he is involved in developing conformal antenna arrays.

Patrik Persson is a research scientist and instructor at the Royal Institute of Technology in Sweden. He is the 2002 recipient of the R.W.P. King Prize Paper Award by the IEEE Antennas and Propagation Society. A frequent collaborator with Dr. Josefsson, he teaches courses on Antenna Theory at RIT and has been a visiting scholar at the ElectroScience Laboratory at Ohio State University.

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This publication is the first comprehensive treatment of conformal antenna arrays from an engineering perspective. There are journal and conference papers that treat the field of conformal antenna arrays, but they are typically theoretical in nature. While providing a thorough foundation in theory, the authors of this publication provide readers with a wealth of hands-on instruction for practical analysis and design of conformal antenna arrays. Thus, readers gain the knowledge they need, alongside the practical know-how to design antennas that are integrated into structures such as an aircraft or a skyscraper.

Compared to planar arrays, conformal antennas, which are designed to mold to curved and irregularly shaped surfaces, introduce a new set of problems and challenges. To meet these challenges, the authors provide readers with a thorough understanding of the nature of these antennas and their properties. Then, they set forth the different methods that must be mastered to effectively handle conformal antennas.

This publication goes well beyond some of the common issues dealt with in conformal antenna array design into areas that include:

• Mutual coupling among radiating elements and its effect on the conformal antenna array characteristics
• Doubly curved surfaces and dielectric covered surfaces that are handled with a high frequency method
• Explicit formulas for geodesics on surfaces that are more general than the canonical circular cylinder and sphere

With specific examples of conformal antenna designs, accompanied by detailed illustrations and photographs, this is a must-have reference for engineers involved in the design and development of conformal antenna arrays. The publication also serves as a text for graduate courses in advanced antennas and antenna systems.

Aus dem Klappentext

This publication is the first comprehensive treatment of conformal antenna arrays from an engineering perspective. There are journal and conference papers that treat the field of conformal antenna arrays, but they are typically theoretical in nature. While providing a thorough foundation in theory, the authors of this publication provide readers with a wealth of hands-on instruction for practical analysis and design of conformal antenna arrays. Thus, readers gain the knowledge they need, alongside the practical know-how to design antennas that are integrated into structures such as an aircraft or a skyscraper.

Compared to planar arrays, conformal antennas, which are designed to mold to curved and irregularly shaped surfaces, introduce a new set of problems and challenges. To meet these challenges, the authors provide readers with a thorough understanding of the nature of these antennas and their properties. Then, they set forth the different methods that must be mastered to effectively handle conformal antennas.

This publication goes well beyond some of the common issues dealt with in conformal antenna array design into areas that include:

• Mutual coupling among radiating elements and its effect on the conformal antenna array characteristics
• Doubly curved surfaces and dielectric covered surfaces that are handled with a high frequency method
• Explicit formulas for geodesics on surfaces that are more general than the canonical circular cylinder and sphere

With specific examples of conformal antenna designs, accompanied by detailed illustrations and photographs, this is a must-have reference for engineers involved in the design and development of conformal antenna arrays. The publication also serves as a text for graduate courses in advanced antennas and antenna systems.

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Conformal Array Antenna Theory and Design

By Lars Josefsson Patrik Persson

John Wiley & Sons

Copyright © 2006 Institute of Electrical and Electronics Engineers, Inc.
All right reserved.
ISBN: 978-0-471-46584-3

Chapter One

INTRODUCTION

1.1 THE DEFINITION OF A CONFORMAL ANTENNA

A conformal antenna is an antenna that conforms to something; in our case, it conforms to a prescribed shape. The shape can be some part of an airplane, high-speed train, or other vehicle. The purpose is to build the antenna so that it becomes integrated with the structure and does not cause extra drag. The purpose can also be that the antenna integration makes the antenna less disturbing, less visible to the human eye; for instance, in an urban environment. A typical additional requirement in modern defense systems is that the antenna not backscatter microwave radiation when illuminated by, for example, an enemy radar transmitter (i.e., it has stealth properties).

The IEEE Standard Definition of Terms for Antennas (IEEE Std 145-1993) gives the following definition:

2.74 conformal antenna [conformal array]. An antenna [an array] that conforms to a surface whose shape is determined by considerations other than electromagnetic; for example, aerodynamic or hydrodynamic.

2.75 conformal array. See: conformal antenna.

Strictly speaking, the definition includes also planar arrays if the planar "shape is determined by considerations other than electromagnetic." This is, however, not common practice. Usually, a conformal antenna is cylindrical, spherical, or some other shape, with the radiating elements mounted on or integrated into the smoothly curved surface. Many variations exist, though, like approximating the smooth surface by several planar facets. This may be a practical solution in order to simplify the packaging of radiators together with active and passive feeding arrangements.

1.2 WHY CONFORMAL ANTENNAS?

A modern aircraft has many antennas protruding from its structure, for navigation, various communication systems, instrument landing systems, radar altimeter, and so on. There can be as many as 20 different antennas or more (up to 70 antennas on a typical military aircraft has been quoted [Schneider et al. 2001]), causing considerable drag and increased fuel consumption. Integrating these antennas into the aircraft skin is highly desirable [Wingert & Howard 1996]. Preferably, some of the antenna functions should be combined in the same unit if the design can be made broadband enough. The need for conformal antennas is even more pronounced for the large-sized apertures that are necessary for functions like satellite communication and military airborne surveillance radars.

A typical conformal experimental array for leading-wing-edge integration is shown in Figure 1.2. The X-band array is conformal with the approximately elliptical cross section shape of the leading edge of an aircraft wing [Kanno et al. 1996]. Figure 1.3 shows an even more realistically wing-shaped C-band array (cf. [Steyskal 2002]).

Array antennas with radiating elements on the surface of a cylinder, sphere, or cone, and so on, without the shape being dictated by, for example, aerodynamic or similar reasons, are usually also called conformal arrays. The antennas may have their shape determined by a particular electromagnetic requirement such as antenna beam shape and/or angular coverage. To call them conformal array antennas is not strictly according to the IEEE definition cited above, but we follow what is common practice today.

A cylindrical or circular array of elements has a potential of 360 coverage, either with an omnidirectional beam, multiple beams, or a narrow beam that can be steered over 360. A typical application could be as a base station antenna in a mobile communication system. Today, the common solution is three separate antennas, each covering a 120 sector. Instead, one cylindrical array could be used, resulting in a much more compact installation and less cost.

Another example of shape being dictated by coverage is shown in Figure 1.4. This is a satellite-borne conical array (and, hence, the drag problem is certainly not an issue here).

The arguments for and against conformal arrays can be discussed at length. The applications and requirements are quite variable, leading to different conclusions. In spite of this, and to encourage further discussion, we present a summary based on reflections by Guy [1999], Guy et al. [1999], Watkins [2001], and others in Table 1.1.

1.3 HISTORY

The field of phased array antennas was a very active area of research in the years from WW II up to about 1975. During this period, much pioneering work was done also for conformal arrays. However, electronically scanned, phased array antennas did not find widespread use until the necessary means for feeding and steering the array became available. Integrated circuit (IC) technology, including monolithic microwave integrated circuits (MMIC), filled this gap, providing reliable technical solutions with a potential for low cost, even for very complex array antennas. An important factor was also the development of digital processors that can handle the enormously increased rate of information provided by phased array systems. Digital processing techniques made phased array antenna systems cost effective, that is, they provided the customers value for the money spent.

This being true for phased arrays in general, it also holds for conformal array antennas. However, in the area of conformal arrays, electromagnetic models and design know-how needed extra development. During the last 10 to 20 years, numerical techniques, electromagnetic analysis methods, and the understanding of antennas on curved surfaces have improved. Important progress has been made in high-frequency techniques, including analysis of surface wave diffraction and modeling of radiating sources on curved surfaces.

The origin of conformal arrays can be traced at least back to the 1930s when a system of dipole elements arranged on a circle, thus forming a circular array, was analyzed by Chireix [1936]. Later, in the 1950s, several publications on the subject were presented; see, for example, [Knudsen 1953a,b]. The circular array was attractive because of its rotational symmetry. Proper phasing can create a directional beam, which can be scanned 360 in azimuth. The applications were in broadcasting, communication, and later also navigation and direction finding. An advanced, more recent application using a large circular array is the French RIAS experimental radar system [Dorey et al. 1989, Colin 1996].

During the Second World War, HF circular arrays were developed for radio signal intelligence gathering and direction finding in Germany. These so-called Wullenweber arrays (code word for the development project) were quite large with a diameter of about 100 meters. After the war, an experimental Wullenweber array was developed at the University of Illinois (see Figure 1.5). This array had 120 radiating elements in front of a reflecting screen. The diameter was about 300 m; note the size of the buildings in the center [Gething 1966]. Many similar systems were built in other countries during the Cold War. Some of these huge antennas may still be operating. See also [IRE PGAP Newsletter Vol. 3, December 1960].

During this period, new, efficient pattern synthesis methods and practical feeding and beam control schemes were investigated by several...

Details zur Ausgabe

• Verlag: Wiley & Sons
• Erscheinungsdatum: 2006
• Sprache: Englisch
• ISBN 10: 0471465844
• ISBN 13: 9780471465843
• Einband: Gebundene Ausgabe
• Auflage: 1
• Anzahl der Seiten: 512
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