Introduction to Antenna Placement and Installation

421 Pages·2010·24.74 MB·English

by  Thereza M. Macnamara(auth.)

INTRODUCTION TO
ANTENNA PLACEMENT
AND INSTALLATION
I ntroduction to A ntenna P lacement & I nstallation Thereza M. Macnamara
© 2010 John Wiley & Sons, L td. ISBN: 978-0-470-01981-8
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INTRODUCTION TO
ANTENNA PLACEMENT
AND INSTALLATION
Thereza M. Macnamara BSc, MSc (London)
A John Wiley and Sons, Ltd., Publication
Thiseditionfirstpublished2010
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LibraryofCongressCataloging-in-PublicationData
Macnamara,Thereza.
Introductiontoantennaplacementandinstallation/TherezaMacNamara.
p.cm.
Includesbibliographicalreferencesandindex.
ISBN978-0-470-01981-8(cloth)
1.Airplanes–Radioantennas–Installation.2.Antennaradiationpatterns.I.Title.
TL694.A6M282010
621.382(cid:2)4–dc22
2010000252
AcataloguerecordforthisbookisavailablefromtheBritishLibrary.
ISBN:9780470019818(Hbk)
Typesetin10/12TimesbyLaserwordsPrivateLimited,Chennai,India.
PrintedinSingaporebyMarkano
This book is dedicated to my three granddaughters Shanti Jasmine
(AKA Cheeky), Sophia Jane Zahra (AKA Softie) and Teya Mared
(AKA Twinks) who will hopefully read it when they are older.
Contents
About the Author xv
Preface xvii
Series Preface xxi
1 Basic Antenna and Propagation Theory 1
1.1 Introduction 1
1.2 Characteristics of Electromagnetic Waves 2
1.2.1 Reflection 3
1.2.2 Refraction 4
1.2.3 Diffraction 8
1.3 Interaction between Two Waves 10
1.3.1 Waveformsin the Time Domain 10
1.3.2 Phasors 12
1.4 Polarization 15
1.4.1 LinearPolarization 16
1.4.2 Circularand Elliptical Polarization 16
1.4.3 AxialRatio 19
1.4.4 Measurementof Polarization Purity 20
1.5 Characteristics of an Antenna 21
1.5.1 Radiation Patterns 22
1.5.2 Directivity,Gain and Efficiency 29
1.5.3 Electricaland MechanicalBoresight 30
1.5.4 Beamwidthand Gain ofthe Main Lobe 30
1.5.5 Position andMagnitude of the Lobes 32
1.5.6 Bandwidth 33
1.5.7 Polarization 35
1.5.8 PowerHandling 36
1.6 Propagation 36
1.6.1 PowerFlux Density 36
1.6.2 GuidedWaves 38
1.6.3 FreeSpace Waves 42
References 44
2 Aircraft Systems Using Antennas 45
viii Contents
2.1 Aircraft Systems 45
2.2 Frequencies of the Most Common Aircraft Systems 46
2.3 Automatic Direction Finding 46
2.4 Distress/SOS 49
2.5 Distance Measuring Equipment 49
2.6 Electronic Counter Measures 50
2.7 Electronic Support Systems 51
2.7.1 Frequency 51
2.7.2 Positional Information 51
2.7.3 DOA from Antenna Position 51
2.7.4 DOA Using Amplitude Comparison 52
2.7.5 DOA Using Phase Comparison 54
2.8 Emergency Locator Transmitter/Emergency Position Indicating
Radio Beacon 55
2.9 Global Positioning System 56
2.10 HF 58
2.11 Instrument Landing System 59
2.11.1 ILSMarker 59
2.11.2 ILSGlideslope and Localizer 60
2.12 In-Flight Telephony 63
2.13 Microwave Landing System 64
2.14 Radar 65
2.14.1 DopplerShift 65
2.14.2 RadAlt 67
2.14.3 SearchRadar 67
2.14.4 WeatherRadar 68
2.14.5 Synthetic Aperture Radar (SAR) 69
2.14.6 SecondarySurveillance Radar 69
2.15 SatCom Civilian 70
2.15.1 INMARSAT 70
2.15.2 Globalstar 71
2.15.3 Iridium 71
2.15.4 SKYLink 71
2.15.5 Teledesic 71
2.15.6 SatCom Airborne Antennas 71
2.16 Signals Intelligence 73
2.16.1 Communications Intelligence 74
2.16.2 Electronic Intelligence 74
2.17 Tactical Air Navigation 75
2.18 Traffic Collision Avoidance System 76
2.19 Telemetry 77
2.20 UHF 78
2.21 VHF Comms 78
2.22 VHF Omnidirectional Ranging 79
2.23 Equipment Designation 80
References 83
Contents ix
3 The Antenna Siting Process 85
3.1 Introduction 85
3.2 New Antenna Layouts 85
3.3 Optimum Positions for Blades 87
3.4 Design Phase 87
3.4.1 Initial Paper DesignStage 88
3.4.2 Investigative and Computational Modelling Phase 91
3.4.3 Verification and ImplementationPhase 95
3.5 Certification and Qualification Phase 97
3.6 Typical Antenna Layouts 97
3.6.1 Small Aircraft 97
3.6.2 LargeAircraft 98
References 101
4 Frequency and Spatial Coverage Considerations 103
4.1 Introduction 103
4.1.1 Standard Ground Planes 103
4.2 Effect of the Structure on the Spatial Characteristics
of the Antenna 104
4.2.1 Uninstalled and Installed Patterns 104
4.3 Combination of Two Waves 105
4.3.1 Combination in the Time Domain 107
4.3.2 Combination of TwoWavesUsing Trigonometry 111
4.4 Measurements on Scaled Test Bodies 114
4.4.1 Fokker100 ScaledModelUsedfor Measurements 114
4.4.2 CylinderUsedfor Radiation Pattern Measurements 115
4.5 Effect of Frequency on the Radiation Pattern 117
4.6 Effect of Distance from Obstacles 117
4.6.1 Effectof the Physical Distance from Obstacles 117
4.6.2 Effectof the Electrical Distance from Obstacles 119
4.7 Effect of Wings on the Radiation Pattern 122
4.8 Effect of the Curved Ground Plane and the Electrical Dimensions
of the Fuselage 124
4.8.1 Effectof the CurvedFuselage on the Roll Plane
Patterns 125
4.8.2 Effectof the CurvedNose Coneand Tail on the Pitch
Plane Patterns 128
4.9 Radiation Patterns on Cylinders in the Absence of Obstacles 130
References 131
5 Antennas Used on Aircraft 133
5.1 Introduction 133
5.2 Near and Far Fields of an Antenna 133
5.2.1 FarField for Wire Antennas 133
5.2.2 FarField for Aperture Antennas 135
5.3 Antennas on Aerostructures 137
x Contents
5.4 Polar Radiation Patterns 138
5.5 Dipoles 138
5.5.1 Small Dipoles 139
5.5.2 Resonant Dipoles 139
5.5.3 Broadband Dipoles 142
5.5.4 CrossedDipoles 142
5.5.5 Dipole Arrays 143
5.6 Monopoles 144
5.6.1 GroundPlane Dependence 145
5.6.2 TopLoadedMonopoles 145
5.6.3 Small Monopoles 147
5.6.4 Broadband Monopoles 148
5.6.5 TunedMonopoles 149
5.6.6 Monopole Arrays 150
5.7 Loops and Notches 150
5.8 Helixes 152
5.9 Flat/Planar Spirals 153
5.10 Patches 156
5.10.1 PatchArrays 156
5.11 Aperture Antennas 157
5.12 Reflectors 157
5.12.1 Antennas andthe Fourier Transform 157
5.13 Waveguide Fed Antennas 170
5.13.1 Waveguide Theory 171
5.13.2 Horns 174
5.13.3 Slotted Waveguide Array Antenna 174
5.13.4 PhasedArray Antennas 175
5.14 Model Numbers Used by Different Manufacturers 176
References 178
6 RF Interoperability 179
6.1 Introduction 179
6.2 Coupling between Systems on an Aircraft 179
6.2.1 ConductedEmissions inside the Airframe 180
6.2.2 Radiated Emissions inside the Airframe 181
6.2.3 Radiated Emissions outside the Airframe 181
6.2.4 ConductedEmissions outside the Airframe 181
6.2.5 Radiated Emissions through the Airframe 182
6.2.6 ConductedEmissions through the Airframe 182
6.2.7 CouplingbetweenSystemsduetoRadiatedEmissionsOutsidethe
Airframe 182
6.3 Techniques for Achieving RF Interoperability 183
6.3.1 AntennaPlacement 184
6.3.2 TimeDomain Measures 184
6.3.3 Sidelobe Blanking 185
6.3.4 ReceiverBlanking 185
Contents xi
6.3.5 FrequencyFilters 186
6.3.6 EM Shielding 187
6.4 Modulation 190
6.4.1 Amplitude Modulation 191
6.4.2 Single Sideband Modulation 192
6.4.3 FrequencyModulation 192
6.4.4 PulsedRadar 193
6.5 Coupling due to Radiated Emissions through the Antennas 194
6.6 Coupling between Systems with LOS Antennas 197
6.6.1 Spatial Isolation 198
6.6.2 Calculation of Coupling betweenSystemswith LOSAntennas 200
6.6.3 Out-of-BandCoupling 204
6.7 Coupling between Systems for Antennas on Opposite Surfaces
of the Fuselage 206
6.7.1 Problemswith Estimating Coupling at the Higher Frequencies 208
6.8 Existing Formulas Used for Calculating Coupling between Two Antennas
on Opposite Surfaces 210
6.8.1 Bull and Smithers 210
6.8.2 Simple Diffraction 213
6.9 Derivation of an Empirical Formula that Correlates with the
Measured Data 217
References 222
7 Computer Modelling Techniques 223
7.1 Introduction 223
7.2 Overview of Computer Modelling 224
7.2.1 Reasonsfor Computer Modelling of Antennason Structures 224
7.2.2 SystemsPerformance Using Antenna Modelling 225
7.2.3 Postdiction 227
7.2.4 Modelling the Exterior Surface 227
7.2.5 Modelling the Antenna 228
7.2.6 TheFrequencyGap 230
7.3 Generic Types of Computer Modelling 230
7.3.1 Classification of Generic Forms ofComputer Packages 231
7.3.2 Verification of Modelling by Showing Correlation with Measured
Data 232
7.4 Method of Moments 232
7.4.1 Enhancements 235
7.4.2 Comparison withScaled ModelMeasurements 238
7.4.3 Fast Multipole Method– BEM with AcceleratedSolver 239
7.5 Finite Difference Time Domain 239
7.5.1 Comparison withMeasurements 241
7.6 GTD/UTD 241
7.6.1 Geometric Theoryof Diffraction 242
7.6.2 Uniform/Unified Theory of Diffraction 243
7.6.3 CreepingWavesAround Cylinders 243