Conformal Array Antenna Theory and Design

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.

• Preface xiAbbreviations and Acronyms xiii1 Introduction 11.1 The Definition of a Conformal Antenna 11.2 Why Conformal Antennas? 21.3 History 41.4 Metal Radomes 91.5 Sonar Arrays 92 Circular Array Theory 152.1 Introduction 152.2 Fundamentals 162.3 Phase Mode Theory 232.4 The Ripple Problem in Omnidirectional Patterns 342.5 Elevation Pattern 412.6 Focused Beam Pattern 413 The Shapes of Conformal Antennas 493.1 Introduction 493.2 360° Coverage 523.3 Hemispherical Coverage 573.4 Multifaceted Surfaces 673.5 References 704 Methods of Analysis 734.1 Introduction 734.2 The Problem 754.3 Electrically Small Surfaces 764.4 Electrically Large Surfaces 894.5 Two Examples 954.6 A Comparison of Analysis Methods 1005 Geodesics on Curved Surfaces 1235.1 Introduction 1235.2 Singly Curved Surfaces 1305.3 Doubly Curved Surfaces 1355.4 Arbitrarily Shaped Surfaces 1496 Antennas on Singly Curved Surfaces 1556.1 Introduction 1556.2 Aperture Antennas on Circular Cylinders 1576.3 Aperture Antennas on General Convex Cylinders 1926.4 Aperture Antennas on Faceted Cylinders 2006.5 Aperture Antennas on Dielectric Coated Circular Cylinders 2096.6 Microstrip-Patch Antennas on Coated Circular Cylinders 2306.7 The Cone 2457 Antennas on Doubly Curved Surfaces 2657.1 Introduction 2657.2 Aperture Antennas 2677.3 Microstrip-Patch Antennas 2898 Conformal Array Characteristics 3058.1 Introduction 3058.2 Mechanical Considerations 3068.3 Radiation Patterns 3138.4 Array Impedance 3278.5 Polarization 3368.6 Characteristics of Selected Conformal Arrays 3519 Beam Forming 3659.1 Introduction 3659.2 A Note on Orthogonal Beams 3669.3 Analog Feed Systems 3669.4 Digital Beam Forming 3809.5 Adaptive Beam Forming 3849.6 Remarks on Feed Systems 38810 Conformal Array Pattern Synthesis 39510.1 Introduction 39510.2 Shape Optimization 39710.3 Fourier Methods for Circular Ring Arrays 39710.4 Dolph-Chebysjev Pattern Synthesis 39810.5 An Aperture Projection Method 40110.6 The Method of Alternating Projections 40410.7 Adaptive Array Methods 40610.8 Least-Mean-Squares Methods (LMS) 40710.9 Polarimetric Pattern Synthesis 40910.10 Other Optimization Methods 40910.11 A Synthesis Example Including Mutual Coupling 41110.12 A Comparison of Synthesis Methods 41411 Scattering From Conformal Arrays 42111.1 Introduction 43111.2 Definitions 42211.3 Radar Cross Section Analysis 42311.4 Cylindrical Array 42711.5 Cylindrical Array with Dielectric Coating 43511.6 Radiation and Scattering Trade-off 44611.7 Discussion 458References 459Subject Index 463About the Authors 471