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. Abbreviations and Acronyms. 1 INTRODUCTION. 1.1 The Definition of a Conformal Antenna. 1.2 Why Conformal Antennas? 1.3 History. 1.4 Metal Radomes. 1.5 Sonar Arrays. References. 2 CIRCULAR ARRAY THEORY. 2.1 Introduction. 2.2 Fundamentals. 2.2.1 Linear Arrays. 2.2.2 Circular Arrays. 2.3 Phase Mode Theory. 2.3.1 Introduction. 2.3.2 Discrete Elements. 2.3.3 Directional Elements. 2.4 The Ripple Problem in Omnidirectional Patterns. 2.4.1 Isotropic Radiators. 2.4.2 Higher-Order Phase Modes. 2.4.3 Directional Radiators. 2.5 Elevation Pattern. 2.6 Focused Beam Pattern. References. 3 THE SHAPES OF CONFORMAL ANTENNAS. 3.1 Introduction. 3.2 360 Coverage. 3.2.1 360 Coverage Using Planar Surfaces. 3.2.2 360 Coverage Using a Curved Surface. 3.3 Hemispherical Coverage. 3.3.1 Introduction. 3.3.2 Hemispherical Coverage Using Planar Surfaces. 3.3.3 Half Sphere. 3.3.4 Cone. 3.3.5 Ellipsoid. 3.3.6 Paraboloid. 3.3.7 Comparing Shapes. 3.4 Multifaceted Surfaces. 3.5 References. 4 METHODS OF ANALYSIS. 4.1 Introduction. 4.2 The Problem. 4.3 Electrically Small Surfaces. 4.3.1 Introduction. 4.3.2 Modal Solutions. 4.3.2.1 Introduction. 4.3.2.2 The Circular Cylinder. 4.3.2.3 A Unit Cell Approach. 4.3.3 Integral Equations and the Method of Moments. 4.3.4 Finite Difference Time Domain Methods (FDTD). 4.3.4.1 Introduction. 4.3.4.2 Conformal or Contour-Patch (CP) FDTD. 4.3.4.3 FDTD in Global Curvilinear Coordinates. 4.3.4.4 FDTD in Cylindrical Coordinates. 4.3.5 Finite Element Method (FEM). 4.3.5.1 Introduction. 4.3.5.2 Hybrid FE-BI Method. 4.4 Electrically Large Surfaces. 4.4.1 Introduction. 4.4.2 High-Frequency Methods for PEC Surfaces. 4.4.3 High-Frequency Methods for Dielectric Coated Surfaces. 4.5 Two Examples. 4.5.1 Introduction. 4.5.2 The Aperture Antenna. 4.5.3 The Microstrip-Patch Antenna. 4.6 A Comparison of Analysis Methods. Appendix 4AInterpretation of the ray theory. 4A.1 Watson Transformation. 4A.2 Fock Substitution. 4A.3 SDP Integration. 4A.4 Surface Waves. 4A.5 Generalization. References. 5 GEODESICS ON CURVED SURFACES. 5.1 Introduction. 5.1.1 Definition of a Surface and Related Parameters. 5.1.2 The Geodesic Equation. 5.1.3 Solving the Geodesic Equation and the Existence of Geodesics. 5.2 Singly Curved Surfaces. 5.3 Doubly Curved Surfaces. 5.3.1 Introduction. 5.3.2 The Cone. 5.3.3 Rotationally Symmetric Doubly Curved Surfaces. 5.3.4 Properties of Geodesics on Doubly Curved Surfaces. 5.3.5 Geodesic Splitting. 5.4 Arbitrarily Shaped Surfaces. 5.4.1 Hybrid surfaces. 5.4.2 Analytically Described Surfaces. References. 6 ANTENNAS ON SINGLY CURVED SURFACES. 6.1 Introduction. 6.2 Aperture Antennas on Circular Cylinders. 6.2.1 Introduction. 6.2.2 Theory. 6.2.3 Mutual Coupling. 6.2.3.1 Isolated Mutual Coupling. 6.2.3.2 Cross Polarization Coupling. 6.2.3.3 Array mutual coupling. 6.2.4 Radiation Characteristics. 6.2.4.1 Isolated-Element Patterns. 6.2.4.2 Embedded-Element Patterns. 6.3 Aperture Antennas on General Convex Cylinders. 6.3.1 Introduction. 6.3.2 Mutual Coupling. 6.3.2.1 The Elliptic Cylinder. 6.3.2.2 The Parabolic Cylinder. 6.3.2.3 The Hyperbolic Cylinder. 6.3.3 Radiation Characteristics. 6.3.3.1 The Elliptic Cylinder. 6.3.3.2 End Effects. 6.4 Aperture Antennas on Faceted Cylinders. 6.4.1 Introduction. 6.4.2 Mutual Coupling. 6.4.3 Radiation Characteristics. 6.5 Aperture Antennas on Dielectric Coated Circular Cylinders. 6.5.1 Introduction. 6.5.2 Mutual Coupling. 6.5.2.1 Isolated Mutual Coupling. 6.5.2.2 Array Mutual Coupling. 6.5.3 Radiation Characteristics. 6.5.3.1 Isolated-Element Patterns. 6.5.3.2 Embedded-Element Patterns. 6.6 Microstrip-Patch Antennas on Coated Circular Cylinders. 6.6.1 Introduction. 6.6.2 Theory. 6.6.3 Mutual Coupling. 6.6.3.1 Single-Element Characteristics