Electronic Scanned Array Design

Description

Electronic Scanned Array Design covers the fundamental principles of ESA antennas including basic design approaches and inherent design limitations. These insights enable better appreciation of existing and planned ESA systems including their application to earth observation. The material describes general design principles of aperture antennas applied to the specific case of ESA design. System applications are discussed to set the framework for requirements allocation and flowdown. Specific examples are cited throughout to relate theory to practice. The book begins by introducing the concept of electronic scanned arrays, giving a brief history of the technology and outlining its scope and applications. Further chapters cover antenna principles; synthetic arrays; antenna figures of merit; mutual coupling effects; errors and tolerances; grating lobes; thinned arrays; beam width and sidelobes; beam shaping and spoiling; reflector applications; design practice; radiating elements; T/R modules; assembly, packaging, power and thermal management; technology base and cost; and ESAs in space. The final chapter offers a comparison between an ESA and a reflector, exploring their benefits, detriments and design trades. The book will be invaluable for radar and antenna engineers and researchers, and advanced students studying ESA design. Cover Half title Series titles Title Copyright Contents List of figures List of tables Preface About the author 1 Introduction 1.1 Overview 1.2 Scope 1.2.1 Antenna evolution 1.2.2 ESA benefits 1.2.3 Types of ESAs 1.3 Early ESA development 1.3.1 F-15 airborne radar 1.3.2 MESAR and the SAMPSON naval radar 1.3.3 Global Protection Against Limited Strike family of radars 1.3.3.1 AN/TPY-2 1.3.3.2 SBX 1.3.4 Concurrent computer development 1.4 ESA applications 1.4.1 Terrestrial ESAs 1.4.1.1 Communications 1.4.1.2 Radar 1.4.2 Communications and internet satellites 1.4.3 Radar satellites 1.4.3.1 Commercial radar satellites 1.4.3.2 Iceye compared to Seasat 1.4.4 Radio astronomy References 2 Antenna principles 2.1 Introduction 2.1.1 Reciprocity 2.1.2 Uniqueness 2.1.3 Sampling and Fourier transforms 2.1.4 Beam shape and resolution 2.2 Electromagnetic radiation 2.3 Maxwell’s equations 2.3.1 Radiating/evanescent solutions 2.3.2 Boundary conditions 2.3.3  Analysis regions (exact to approximate) 2.3.3.1 Single four-lambda wide slot 2.4 Aperture shape 2.4.1 Rectangular aperture 2.4.1.1 Uniform distribution on an infinite ground plane 2.4.1.2 Power 2.4.1.3 Beamwidths 2.4.2 Circular aperture Caveat 2.5 Discrete case 2.5.1 Element contribution 2.5.1.1 Fraunhofer approximation 2.5.2 Array factor 2.5.2.1 Pattern separability 2.5.2.2 Decomposition in X and Y 2.5.2.3 Pattern multiplication 2.5.2.4 16 element array = 4 × 4 element array 2.5.3 One-dimensional beamformation (boresight) 2.5.3.1 Maximum gain 2.5.3.2 Selected boresight case (M = 10) 2.6 Beam steering 2.6.1 Beam-steering geometric construction 2.6.2 One-dimensional beamformation (steered) 2.6.2.1 Scanned array factor 2.6.2.2 Selected steered (30°) case (M = 10) 2.6.3 Beam squint 2.6.3.1 Phase shift and bandwidth 2.6.3.2 Time delay 2.6.3.3 Time delay steering eliminates beam squint 2.7 Feed and beamforming networks 2.7.1 Feed networks 2.7.2 Beamforming networks 2.7.2.1 Butler matrix beamformer 2.7.2.2 Blass matrix beamformer 2.8 Subarray partitioning and recombination 2.8.1 Array partitioning 2.8.1.1 Beam squint revisited phase-steered 0.5 m array 2.8.1.2 Beam squint revisited phase-steered 4 m array 2.8.1.3 Eight time-delayed 0.5 m subarrays 2.8.2 Overlapped subarray 2.8.3 Scan constraint summary References 3 Synthetic arrays 3.1 Synthetic aperture radar 3.1.1 SAR and Doppler 3.1.2 SAR and holography 3.2 Near-field scanning 3.3 Interferometry References 4 Antenna figures of merit 4.1 Beam shape, sidelobes, and nulls 4.1.1 Amplitude weighting 4.1.2 Peak sidelobe ratio 4.1.3 Integrated sidelobe ratio 4.1.4 Two-way patterns Circular arrays Bistatic case 4.2 Efficiency and scattering 4.2.1 Aperture (utilization) efficiency 4.3 Resolution and bandwidth 4.4 Noise and dynamic range 4.4.1 Noise figure 4.4.2 Array noise figure model 4.4.3 Effect of aperture taper 4.4.4 Dynamic range (third-order intercept) 4.5 System performance equations 4.5.1 SAR equation (NESZ) 4.5.2 Radar range equation 4.5.3 Friis transmission equation References 5 Mutual coupling effects 5.1 Definition 5.2 Problem 5.3 Parametric analysis 5.4 Patch element example 5.5 Waveguide element example 5.6 Dipole example References 6 Errors and tolerances 6.1 Random and deterministic errors 6.2 Amplitude error 6.3 Phase error 6.4 Calibration References 7 Grating lobes 7.1 Lattice attributes 7.2 Grating lobes location Grating lobes in (u, v) space (rectangular lattice) Grating lobes in (u. v) space (triangular lattice) Scan volume comparison 7.3 Superresolution 7.4 Linear array examples 7.5 Grating lobe suppression Reference 8 Thinned arrays 8.1 Random thinning 8.2 Effects of amplitude errors 8.3 Systematic thinning for amplitude taper References 9 Beamwidth and sidelobes 9.1 Schelkunoff representation Schelkunoff theorems Single beam Addition of missing root Two slits separated by 5.5‍ 9.2 Uniform weighting (unweighted) Uniform example (M = 11) 9.3 Triangular weighting Triangular example (M = 11) 9.4 Binomial weighting Binomial example (M = 11) 9.5 Dolph–Chebyshev Chebyshev polynomials Aperture weight derivation Result Dolph–Chebyshev example (M = 11) 9.6 Taylor weighting 9.7 Beam performance comparisons References 10 Beam shaping and spoiling 10.1 Fourier synthesis technique Fourier transform synthesis Fourier transform – first null Fourier transform – second null Fourier transform – third null 10.2 Woodward–Lawson synthesis 10.3 Phase-only beam broadening Quadratic beam spoiling Quadratic phase example Beam spoiling and Taylor weighting References 11 Reflector applications 11.1 Configurations 11.2 Single reflector 11.3 Dual reflector 11.4 Offset reflector 11.5 Feed design 11.6 Scan limitations References 12 Design practice 12.1 Design tradeoffs 12.2 Architecture Array partitioning 12.3 Design verification References 13 Radiating elements 13.1 Requirements 13.2 Dipole radiating element Coupled dipole arrays 7–21 GHz dual-polarized array 13.3 Horn and waveguide radiating elements 13.3.1 Horn feeds 13.3.2 Slotted waveguide 13.3.2.1 TerraSAR-X first generation 13.3.2.2 Next-generation TerraSAR-X 13.4 Flared notch radiating element Square Kilometer Array application 13.5 Patch radiating element References 14 T/R modules 14.1 Requirements 14.2 Module styles 14.2.1 Brick module configuration 14.2.1.1 European example 14.2.2 Tile module configuration 14.2.2.1 UK example 14.2.2.2 Module packaging 14.2.3 Planar configuration 14.3 Monolithic microwave integrated circuits 14.4 Gain control 14.5 Phase shifters and time delay units 14.5.1 Time delay units 14.5.2 Lumped element delay line 14.5.3 High-pass/low-pass phase shifter 14.5.3.1 Tee filter analysis 14.5.3.2 High-pass filter analysis 14.5.3.3 Input and output matching 14.5.4 Phase shifter benefits and limitations 14.6 Switches and isolators References 15 Assembly, packaging, power, and thermal management 15.1 Assembly 15.2 Test 15.3 Installation 15.4 Packaging 15.5 Power 15.6 Thermal management Thermal design Thermal measurement Array cooling Radiative equilibrium ESA temperature as a function of areal RF density References 16 Technology base and cost 16.1 Government investment laid foundation 16.2 Industrial consolidation for military products 16.3 Commercial investment for consumer products 16.4 T/R module cost reduction since 1980 16.4.1 Congressional Budget Office report Alternatives for Military Space Radar – A CBO Study [18, p. 51] 16.4.2 Manufacturing technology Manufacturing Technology For Radar Transmit / Receive Modules [19] Manufacturing Research and Development of X-Band Active Electronically Scanned Array Transmit/Receive Modules [20] 16.4.3 ESA prices Boeing Company, Space & Security awarded $558,462,269 (November 30, 2016) [21] Northrop Grumman Systems Corporation awarded $243,873,277 (May 31,2017) [22] Raytheon Awarded $212 Million Contract for Terminal High Altitude Area Defense Radar [23] EADS Delivers 5,000 T/R Modules for MEADS Radar, February 3, 2009 [25] 16.4.4 Commercial examples References 17 ESAs in space 17.1 Iridium communications satellite Beams in (u, v) space Beams on globe Beams on globe (detail) Beams projected to ground 17.2 Radar satellites 17.2.1 SAR from space 17.2.1.1 Resolution 17.2.2 Radar satellite geometry and timing 17.2.3 Satellite SAR systems 17.2.4 RF power and thermal densities 17.3 X-band systems 17.3.1 TerraSAR-X 17.3.2 COSMO-SkyMed 17.3.2.1 Antenna beams in ‍ ‍ space 17.3.2.2 Antenna beams on globe 17.3.2.3 Antenna beams on globe (detail) 17.3.2.4 Antenna beams projected to ground 17.4 C-band systems 17.4.1 RadarSAT-2 17.4.2 Sentinel-1 17.5 L-band systems 17.5.1 SeaSAT 17.5.2 Space shuttle radars 17.5.3 Advanced land observing satellites 17.5.3.1 ALOS-2 PALSAR array 17.5.4 SAOCOM References 18 ESA and reflector comparison 18.1 ESA-fed reflector design approach 18.2 Reference designs 18.2.1 DESDynI 18.2.2 NISAR 18.2.3 TanDEM-L 18.3 Offset reflector model Feed pattern overilluminates reflector Individual beam patterns principal planes cut Transmit beam comprises sum of 24 feeds 24 element sum principal plane cuts Reflector beam gain variation Equivalent aperture sizes for reflector Currents in reflector 18.4 ESA conceptual design 18.4.1 Array lattice 18.4.2 Array height 18.4.3 Beam weighting in elevation 18.4.4 Array length 18.4.5 Unthinned ESA 18.4.6 Subarray size 18.4.7 Power and noise figure 18.4.8 Beam projection 18.4.9 Subarray effects 18.4.10 Antenna pattern – boresight and steered 18.4.11 Azimuth cut steered in azimuth 18.4.12 Elevation cut steered in elevation 18.4.13 ESA beamwidth fairly constant with scan 18.4.14 Gain as a function of scan 18.5 Comparison 18.5.1 Array 18.5.2 Feeds 18.5.3 Launch constraints 18.6 Summary References Appendix A. Further reading A.1 Books A.2 Web based References Appendix B. Comments on MATLAB® code B.1 Web resources References Appendix C. Geometry C.1 Coordinate systems C.2 Satellite geometry C.2.1 Geometric relationships C.2.2 Ground swath Reference Index