Satellite Ground Station Antennas

Auteur

Roland Schwerdtfeger was a Life Member of the IEEE with decades of experience in ground station design and operation, achieving global recognition as the definitive expert.

Thomas A. Milligan has served as Principal Engineer for numerous advanced antenna design projects and NASA planetary probes. He is an IEEE Life Fellow and former longtime editor of the "Antenna Designer's Notebook" column in the IEEE Antenna Magazine.

Robert Hoferer, PhD, has 30 years' experience in antenna feed systems and reflector antennas for satellite communication. A Senior Member of the IEEE, he has served since 2013 as co-founder and Chief Technology Officer for Spacetime Engineering.

Christophe Granet, PhD, is an award-winning antenna engineer with over 30 years' experience, and founder of Lyrebird Antenna Research Ltd. He is a Senior Member of the IEEE and in 2001 received the H.A. Wheeler Award from the IEEE Antennas and Propagation Society.

Texte du rabat

Understand all aspects of ground station design with this groundbreaking volume A satellite ground station is a terrestrial station built to communicate or receive signals from spacecraft and other astronomical and interplanetary sources. Since ground stations are subject to weather and other terrestrial conditions, their operations can be unpredictable, and their design offers numerous challenges for engineers. Satellite Ground Station Antennas constitutes the first-ever comprehensive overview of these challenges and the tools by which engineers of all kinds can meet them. Analyzing every aspect of ground station antenna technology, the book can be read both continuously or as a reference, with each chapter functioning by itself to fully apprehend a discrete portion of the subject. Balancing mathematics with mechanics, it combines accessibility and rigor to create an unprecedented resource. Readers will also find:

• In-depth material published in a fully accessible form for the first time
• Detailed discussion of topics including reflector design, structural considerations, proof-of-performance, and more
• Lavish illustrations and photographs throughout Satellite Ground Station Antennas is ideal for electrical, mechanical, and civil engineers, as well as for any other industry professional working with ground station design.

Contenu

About the Authors xix

Preface xxi

Acknowledgments xxiii

Glossary of Terms xxv

Introduction xxxi

1 Antenna System Analysis 1

1.1 Introduction 1

1.2 Antenna Radiation and Path Loss 1

1.3 Polarization 3

1.3.1 Polarization Efficiency 4

1.4 Geometry of Satellite Communication Link 5

1.4.1 Pointing Angles to Satellites 5

1.4.1.1 The Case for the Elevation-over-Azimuth Antenna 5

1.4.1.2 The Case for the Declination-over-Hour Angle Antenna 8

1.4.2 Elevation-over-Azimuth Pattern Angle Correction 10

1.4.3 Sun Outage 10

1.4.4 Linear Polarization Twist at Ground Station from Satellite 11

1.5 Noise in Antennas 12

1.5.1 Noise Mechanisms 12

1.5.2 Signal-to-Noise Ratio 13

1.5.3 Noise Power 13

1.5.4 Equivalent Noise Temperature 14

1.5.5 Noise Figure 14

1.5.6 Antenna Noise Temperature 16

1.5.7 Noise in a Satellite-Earth Station Link 17

1.5.8 Antenna Noise Temperature Components 18

1.5.8.1 Sky Noise 18

1.5.8.2 Antenna Noise Temperature 21

1.5.9 Sky Noise Temperature Variation with Ambient Temperature and Humidity 25

1.6 Interference in Antennas 29

1.6.1 Introduction 29

1.6.1.1 Sources of Interference 30

1.6.1.2 Corrective Filter Application 30

1.6.2 Interference by the Transmitter 31

1.6.3 Interference by Tx Signal Power 33

1.6.4 Interference due to Tx Noise Power 35

1.7 Passive Intermodulation in Antennas 39

1.7.1 Brief History 39

1.7.2 Theory 39

1.7.2.1 Second-Order PIM - Two Equal Amplitude Transmit Carriers 40

1.7.2.2 Third-Order PIM - Two Equal Amplitude Transmit Carriers 40

1.7.2.3 Third-Order PIM - Three Equal Amplitude Transmit Carriers 40

1.7.2.4 Specific Cases of PIM Frequencies 41

1.7.2.5 Amplitude of PIMs 41

1.7.2.6 Causes of PIM in Antennas 45

1.7.3 Some Interesting Observations 46

1.7.3.1 Measurement of PIMs 47

1.8 Link Analysis 47

1.8.1 Uplink Analysis 47

1.8.2 Downlink Analysis 50

1.8.3 EIRP and Power Density 52

1.9 Digital Communication Link Budget 54

1.9.1 Link Budget Supplied by Marc R. Björkman for Commercial Satellite Multichannel TV Transmission 54

References 55

2 Reflector Design 57

2.1 Introduction 57

2.2 Single Reflector Antenna 59

2.2.1 Prime Focus Antenna Efficiency Components 60

2.2.1.1 Phase Error Loss 61

2.2.1.2 Illumination Loss 62

2.2.1.3 Spillover Loss 63

2.2.1.4 Blockage 63

2.2.1.5 Polarization Loss 64

2.2.1.6 Reflector Panel Loss 64

2.2.1.7 Reflection Loss 64

2.2.1.8 Feed Terminal Losses 64

2.2.1.9 Summary 64

2.2.2 General Performance Features 65

2.3 Two-Reflector Design 65

2.3.1 Cassegrain and Gregorian Configurations 65

2.3.2 Antenna Efficiency Components 68

2.3.2.1 Subreflector Blockage 68

2.3.2.2 Subreflector Support Structure Blockage 68

2.3.2.3 Feed Blockage 68

2.3.2.4 Diffraction Loss 70

2.3.2.5 General Performance Features 70

2.3.3 Shaped Reflector Design Considerations 71

2.3.3.1 General Performance Features of the Shaped System 77

2.3.4 The Ring Focus Antenna 78

2.3.4.1 Positive Features of Ring Focus 78

2.3.4.2 Negative Features of the Ring Focus 78

2.3.4.3 General Performance Features 79

2.4 Offset Reflector Antennas 80

2.4.1 Single Offset Reflector Antenna 80

2.4.1.1 Cross-pol Matched Feed System for Single Offset Reflector Applications 87

2.4.2 Horn Reflector 87

2.4.3 Dual-Offset Antennas - Cassegrain and Gregorian 92

2.4.4 Dragonian Reflector System 97

2.5 Characteristics of Antenna Patterns 97

2.5.1 Concept of Antenna Pattern Gain 102

2.6 Antennas with Simultaneous Multiband Feeds 105

2.6.1 Single Aperture Feed Horn 105

2.6.2 Wideband Feed Horn 108

2.6.3 Concentric Aperture Feed Horns 110

2.6.4 Dual Aperture Feeds with FSS 111

2.7 Selectable Multi-feed Systems 111

2.8 Beam Waveguide 115

2.8.1 Introduction 115

2.8.2 Large Antenna Beam Waveguide 115

2.8.3 The Quasi-Beam Waveguide 122

2.9 Multibeam Antennas 123

2.9.1 Introduction 123

2.9.2 The Torus 126

2.9.2.1 The Declination Difficulty and Off-Axis Feed Settings 128

2.9.2.2 Phase Aberrations in the Feed Horn 133

2.9.2.3 Siting the Torus to Other Latitudes 133

2.9.2.4 General Performance Features of the Torus 135

2.9.3 Shaped Cassegrain CSIRO MBA Antenna 139

References 139

3 Feed System Design 141

3.1 Introduction 141

3.2 Linearly Polarized Rx Feed Design and Configurations 142

3.2.1 Example Satellite Link 142

3.2.2 Single Linear Polarization - with Polarization Rotation 146

3.2.3 Dual Linear Polarization - Receive Only 148

3.2.4 Linearly Polarized Tx/Rx Feed Design and Configurations 149

3.2.5 Linear Polarization - Two Orthogonal Rx and One Tx 151

3.2.6 Dual Linear Polarized Rx and Tx 153

3.3 Circular Polarization (CP) - Rx-Only Feed Configurations 157

3.3.1 OMT + 90 Power Divider 158

3.3.2 Differential Phase Shifter with OMT 160

3.3.3 Septum-OMT 164

3.3.4 OMT with Rectangular Horn 167

3.4 Two-Port Circularly Polarized Rx/Tx Feed Systems 168

3.4.1 Four-Port CP Feed Network 171

3.5 Polarization Rotation and Switching 173

3.5.1 90 Differential Phase Shifter - CP/LP Selection 173

3.5.2 180 Differential Phase Shifter - LP Angle Adjust Only 174

3.5.3 CP/LP and LP Angle Adjust 176

3.5.4 90 Differential Phase Shifter - CP Adjust 178

3.5.5 CP/LP Selection - Two-Port Rx/Tx Feed 178

3.6 Combined Dual-Polarized Tx/Rx Feed Configuration 179

3.6.1 Single QJ and Magic Tee Feed System Network Layout 180

3.6.2 Twin-QJ Feed Sys…