PREFACE xix
ACKNOWLEDGMENTS xxi
ABOUT THE AUTHOR xxiii
ABBREVIATIONS xxv
1 INTRODUCTION 1
1.1 What This Book Is About / 1
1.2 Payload / 3
1.2.1 Bent-Pipe Payload Transponder / 4
1.2.2 Processing Payload / 5
1.2.3 Overall Payload Architecture / 6
1.3 Conventions / 6
1.4 Book Sources / 7
1.5 Summary of Rest of the Book / 7
References / 9
PART I PAYLOAD
2 PAYLOAD’S ON-ORBIT ENVIRONMENT 13
2.1 What Determines Environment / 13
2.1.1 Orbit / 13
2.1.2 GEO Spacecraft’s General Layout and Orientation / 15
2.1.3 GEO Spacecraft’s Payload Configuration / 17
2.1.4 Non-GEO Spacecraft Considerations / 18
2.2 On-Orbit Environment / 20
2.2.1 Thermal / 20
2.2.1.1 Cold of Space / 20
2.2.1.2 Heat from Spacecraft Electronics / 20
2.2.1.3 Changing Direction of Sun from Satellite / 20
2.2.1.4 Changing Distance of Sun from Earth / 22
2.2.1.5 Eclipse / 22
2.2.1.6 Mitigation by Bus Thermal-Control Subsystem / 23
2.2.2 Bus and Payload Aging / 25
2.2.3 Radiation / 25
2.2.4 Spacecraft Attitude Disturbances / 27
2.3 General Effects of Environment on Payload / 27
2.3.1 Temperature-Variation Effects / 27
2.3.1.1 On Active Units / 28
2.3.1.2 On RF Lines / 28
2.3.1.3 On Passive Filters / 28
2.3.2 Radiation Effects / 29
2.3.3 Aging Effects / 30
2.3.4 Antenna Gain Variation / 30
References / 31
3 ANTENNA 33
3.1 Introduction / 33
3.2 General Antenna Concepts / 35
3.2.1 Beams / 35
3.2.2 Aperture / 37
3.2.3 Antenna Pattern / 37
3.2.3.1 Gain, EIRP, and G/Ts / 38
3.2.3.2 Far Field and Near Field / 39
3.2.3.3 Gain Pattern / 41
3.2.3.4 Polarization / 42
3.2.4 Orthomode Transducer and Polarizer / 43
3.2.5 Cross-Polarization Induced by Antenna / 44
3.2.6 Diplexer / 45
3.2.7 Losses and Antenna Temperature / 45
3.2.8 Reconfigurability / 47
3.2.9 On-Orbit Environment and Its Mitigation / 47
3.3 Single-Beam Reflector Antenna / 48
3.3.1 Reflector Antenna Concepts / 48
3.3.2 Single-Reflector Single-Beam Antenna / 50
3.3.3 Dual-Reflector Single-Beam Antenna / 51
3.3.3.1 Center-Fed / 51
3.3.3.2 Offset-Fed / 53
3.4 Horn / 54
3.4.1 Types of Horn / 54
3.4.2 Horn as Antenna / 55
3.4.3 Horn as Feed for Single-Beam Reflector Antenna / 56
3.5 Antenna Array / 57
3.5.1 Array Principle / 57
3.5.2 Antenna Array Characteristics / 58
3.5.3 Array Antenna / 59
3.5.4 Array Radiating Elements / 60
3.5.5 Passive and Active Arrays / 61
3.5.6 Beam-Forming / 63
3.5.7 Semiactive Array with Multimatrix Amplifier / 64
3.6 Reflector-Based Multibeam Antenna / 64
3.6.1 Reflector MBA Concepts / 64
3.6.2 Reflector MBAwith Feed Cluster / 65
3.6.3 Reflector MBAwith Array Feeds / 67
3.6.4 Reflector MBAwith Overlapping Feeds / 67
3.7 Autotrack / 68
Appendix 3.A / 70
3.A.1 Decibel / 70
3.A.2 Antenna Pattern of General Aperture / 71
3.A.3 Antenna Pattern of Antenna Array / 72
References / 73
4 FILTER AND PAYLOAD-INTEGRATION ELEMENTS 79
4.1 Introduction / 79
4.2 Impedance Mismatch / 80
4.3 RF Lines for Payload Integration / 82
4.3.1 Coaxial Cable / 83
4.3.1.1 Coax Construction / 83
4.3.1.2 Coax Performance / 85
4.3.1.3 Coax Environmental / 85
4.3.1.4 Connector and Adapter / 86
4.3.1.5 Propagation in Coax / 87
4.3.2 Waveguide / 88
4.3.2.1 Rectangular Waveguide Construction / 88
4.3.2.2 Rectangular Waveguide Performance / 90
4.3.2.3 Waveguide Environmental / 91
4.3.2.4 Flange and Waveguide Assemblies / 91
4.3.2.5 Propagation in Rectangular and Circular Waveguide / 91
4.4 Other Payload-Integration Elements Aside from Switch / 94
4.5 Filter / 97
4.5.1 General / 97
4.5.1.1 Filter Types / 97
4.5.1.2 Filter-Response Families / 98
4.5.1.3 Resonator in General / 99
4.5.1.4 Filter in General / 99
4.5.2 Filter Technology / 101
4.5.2.1 Empty-Cavity Waveguide Filter / 101
4.5.2.2 Dielectric-Resonator Filter / 103
4.5.2.3 Coaxial-Cavity Combline Filter / 104
4.5.3 Filter Unit and Assemblies / 107
4.5.3.1 Preselect Filter / 107
4.5.3.2 Multiplexer in General / 108
4.5.3.3 Input Multiplexer / 108
4.5.3.4 Output Multiplexer / 109
4.5.3.5 Summary of Filter-Technology Application / 110
4.5.4 Filter Specification / 110
4.6 Switch and Redundancy / 111
4.6.1 Switch / 111
4.6.2 Redundancy / 112
Appendix 4.A / 116
4.A.1 Filter Poles and Zeros / 116
References / 117
5 LOW-NOISE AMPLIFIER AND FREQUENCY CONVERTER 123
5.1 Introduction / 123
5.2 Low-Noise Amplifiers and Frequency Converters in Payload / 124
5.2.1 Architecture in Payload / 124
5.2.2 Redundancy Scheme / 124
5.2.3 Combining / 125
5.3 Intermodulation Products / 126
5.4 Low-Noise Amplifier / 127
5.4.1 LNA Unit Architecture and Technology / 127
5.4.2 LNA Linearity / 128
5.4.3 LNA Environmental / 129
5.4.4 LNA Specification / 130
5.5 Frequency Converter / 132
5.5.1 Frequency Conversion Architecture / 132
5.5.2 Phase Noise Introduction / 133
5.5.3 Frequency-Converter Unit Architecture and Function / 134
5.5.4 Mixer / 136
5.5.5 Reference Oscillator / 137
5.5.6 Local Oscillator / 138
5.5.6.1 Phase-Locking Introduction / 138
5.5.6.2 Dielectric-Resonator Oscillator and Coaxial-Resonator Oscillator / 139
5.5.6.3 Frequency Synthesizer / 140
5.5.7 Frequency Converter Linearity / 140
5.5.8 Frequency Converter Environmental / 141
5.5.9 Frequency Converter Specification / 141
Appendix 5.A / 142
5.A.1 Formula for Integrating Phase Noise Spectrum / 142
References / 143
6 PREAMPLIFIER AND HIGH-POWER AMPLIFIER 147
6.1 Introduction / 147
6.2 High-Power Amplifier Concepts and Terms / 148
6.2.1 HPA Nonlinearity Description / 148
6.2.2 HPA Nonlinearity Specification Parameters / 151
6.2.3 Power Efficiency / 153
6.3 Traveling-Wave Tube Amplifier versus Solid-State Power Amplifier / 153
6.4 Traveling-Wave Tube Amplifier Subsystem / 155
6.4.1 Introduction / 155
6.4.2 TWTA Subsystems in Payload / 156
6.4.2.1 Architecture in Payload, Traditional and Flexible / 156
6.4.2.2 Combining / 157
6.4.2.3 Redundancy Scheme / 158
6.4.3 TWTA Subsystem Architecture / 159
6.4.4 Channel Amplifier / 159
6.4.4.1 (L)CAMP Unit Architecture and Technology / 159
6.4.4.2 CAMP Specification / 161
6.4.5 Linearizer / 161
6.4.5.1 Linearizer Architecture and Technology / 161
6.4.5.2 LTWTA Nonlinear Performance / 163
6.4.6 TWTA / 164
6.4.6.1 Electronic Power Conditioner / 164
6.4.6.2 TWT Architecture and Technology / 164
6.4.6.3 (L)TWTA Specification / 167
6.4.7 TWTA Subsystem Performance / 167
6.4.8 Flexible TWTA Subsystem / 168
6.4.9 TWTA Subsystem Environmental / 169
6.4.9.1 Temperature / 169
6.4.9.2 Radiation / 169
6.4.9.3 Aging / 169
6.5 Solid-State Power Amplifier / 170
6.5.1 SSPAs in Payload / 170
6.5.1.1 Architecture in Payload, Traditional and Flexible / 170
6.5.1.2 Redundancy Scheme / 172
6.5.2 SSPA Unit Architecture and Technology / 172
6.5.3 Linearized SSPA / 173
6.5.4 Flexible SSPA / 173
6.5.5 SSPA Environmental / 174
6.5.6 SSPA Specification / 175
References / 176
7 PAYLOAD’S COMMUNICATIONS PARAMETERS 181
7.1 Introduction / 181
7.2 Gain Variation with Frequency / 184
7.2.1 What Gain Variation with Frequency Is / 184
7.2.2 Where Gain Variation with Frequency Comes From / 185
7.2.3 How Gain Variations with Frequency at Unit Level Carry to Payload Level / 186
7.2.4 How to Verify Gain Variation with Frequency / 187
7.3 Phase Variation with Frequency / 187
7.3.1 What Phase Variation with Frequency Is / 187
7.3.2 Where Phase Variation with Frequency Comes From / 188
7.3.3 How Phase Variations with Frequency at Unit Level Carry to Payload Level / 189
7.3.4 How to Verify Phase Variation with Frequency / 189
7.4 Channel Bandwidth / 189
7.5 Phase Noise / 190
7.6 Frequency Stability / 190
7.7 Spurious Signals from Frequency Converter / 191
7.8 High-Power Amplifier Nonlinearity / 192
7.9 Spurious Signals from High-Power Amplifier Subsystem / 192
7.9.1 What HPA-Subsystem Spurious Signals Are / 192
7.9.2 Where HPA-Subsystem Spurious Signals Come From / 193
7.9.3 How HPA-Subsystem Spurious Signals Carry to Payload Level / 194
7.9.4 How to Verify HPA-Subsystem Spurious Signals / 194
7.10 Stability of Gain and Power-Out of High-Power Amplifier Subsystem / 194
7.10.1 What Gain Stability and Power-Out Stability Are / 194
7.10.2 Where Gain Stability and Power-Out Instability Come From / 194
7.10.3 How Gain Stability and Power-Out Stability Carry to Payload Level / 195
7.10.4 How to Verify Gain Stability and Power-Out Stability / 195
7.11 Equivalent Isotropically Radiated Power / 195
7.12 Figure of Merit G/Ts / 196
7.12.1 What G/Ts Is / 196
7.12.2 How to Verify G/Ts / 198
7.13 Self-Interference / 199
7.13.1 What Self-Interference Is / 199
7.13.2 Where Self-Interference Comes From / 199
7.13.3 How Self-Interference Carries to Payload Level / 200
7.13.4 How to Verify Self-Interference / 200
7.14 Passive Intermodulation Products / 201
Appendix 7.A / 201
7.A.1 Antenna Testing / 201
7.A.2 Relation of Gain and Phase Ripple / 202
7.A.3 Independence of G/Ts on Reference Location / 203
References / 204
8 MORE ANALYSES FOR PAYLOAD DEVELOPMENT 207
8.1 Introduction / 207
8.2 How to Deal with Noise Figure / 208
8.2.1 Defining Noise Figure / 208
8.2.2 Noise Temperature at Input and Output of Passive Element / 209
8.2.3 Gain and Noise Figure of Two-Element Cascade / 209
8.2.4 Playing Off Gains and Attenuations / 209
8.3 How to Make and Maintain Payload Performance Budgets / 211
8.3.1 Example Budget without Uncertainty: Signal and Noise Levels / 211
8.3.2 Dealing with Uncertainty in Budgets / 214
8.3.2.1 Two General Ways of Dealing with Uncertainty / 214
8.3.2.2 Types of Line-Item Uncertainty / 214
8.3.2.3 Easy Dealing with Some Uncertainty Types / 215
8.3.2.4 Dealing with Error in Power Measurement / 216
8.3.2.5 Specifying Environment in Lifetime on Which Payload Performance Must Be Met / 217
8.3.2.6 Dealing with Uncertainty from Aging and Radiation / 217
8.3.2.7 Converting Thermal Environment in Lifetime into Unit Temperature Variations / 217
8.3.2.8 Dealing with Performance Variation with On-Orbit Temperature / 219
8.3.2.9 Nominal Value / 220
8.3.2.10 Combining Line-Item Uncertainties / 221
8.3.3 Keeping Margin in Budgets / 222
8.3.4 Maintaining Budget Integrity / 223
8.4 High-Power Amplifier Topics / 223
8.4.1 How to Know If HPA Nonlinearity Should Be Specified on C/3IM or NPR / 223
8.4.2 What HPA Nonlinearity Does to Signal / 224
8.4.2.1 HPA in Terms of Intermodulation Products / 225
8.4.2.2 HPA in Terms of Spectrum-Spreading / 227
8.4.2.3 HPA in Terms of Power Robbing / 227
8.4.3 How to Ease Payload Integration of Combined TWTAs / 228
8.5 How to Avoid Monte Carlo Simulations on Gaussian Random Variables / 231
Appendix 8.A / 232
8.A.1 Elements of Probability Theory for Payload Analysis / 232
8.A.2 Definition of Random Variable and Probability Density Function / 232
8.A.3 Mean, Standard Deviation, and Correlation / 233
8.A.4 Sum of Random Variables / 234
8.A.5 Gaussian Probability Density Function / 235
8.A.6 Uniform and Panel-Illumination Probability Density Function / 237
8.A.7 Standard Deviation of Drift of Unknown Magnitude and Direction / 238
References / 239
9 PROCESSING PAYLOAD 241
9.1 Introduction / 241
9.2 Capabilities of Current Processing Payloads / 242
9.3 Digital-Processing Elements Common to Both Nonregenerative and Regenerative Payloads / 245
9.3.1 A-to-D Converter / 245
9.3.2 D-to-A Converter / 246
9.3.3 Digital Filtering / 247
9.4 Nonregenerative Processing-Payload / 248
9.4.1 Payload Architecture / 248
9.4.2 Analog Channelizer and Router / 248
9.4.3 Digital Channelizer and Router / 249
9.4.4 Digital Beam-Former / 249
9.5 Regenerative Payload / 250
9.5.1 Introduction / 250
9.5.2 Current Regenerative Payloads in TV Broadcast Network / 251
9.5.3 Current Regenerative Payloads in Mesh Network / 253
References / 254
PART II PAYLOAD IN END-TO-END COMMUNICATIONS SYSTEM
10 PRINCIPLES OF DIGITAL COMMUNICATIONS THEORY 259
10.1 Introduction / 259
10.2 Communications Theory Fundamentals / 260
10.2.1 Signal Representation / 260
10.2.1.1 RF Signal Representation / 260
10.2.1.2 RF Signal Equivalent Baseband Representation / 260
10.2.2 Spectrum Fundamentals / 262
10.2.3 Filtering Fundamentals / 264
10.2.3.1 Filter Representation / 264
10.2.3.2 Types of Filter Bandwidth / 266
10.2.4 End-to-End Communications System Fundamentals / 267
10.3 Modulating Transmitter / 268
10.3.1 Architecture / 268
10.3.2 Encoder / 269
10.3.3 Baseband Modulator / 270
10.3.3.1 Modulation Schemes / 271
10.3.3.2 Gray Coding / 274
10.3.4 Pulse Filter and Signal Spectrum / 274
10.3.4.1 Introduction / 274
10.3.4.2 Rectangular Pulse / 275
10.3.4.3 Root Raised-Cosine Pulse / 277
10.3.4.4 MSK Pulse / 277
10.4 Filters / 278
10.4.1 Definitions of Even, Odd, Conjugate Symmetric, and Conjugate Antisymmetric Functions / 278
10.4.2 Real and Imaginary Impulse Responses and Intersymbol Interference / 279
10.5 Demodulating Receiver / 281
10.5.1 Architecture / 281
10.5.2 Carrier Recovery / 281
10.5.3 Detection Filter and Sampler / 283
10.5.3.1 What to Use as Detection Filter / 283
10.5.3.2 What Detection Filter Output from Signal Looks Like / 285
10.5.3.3 Timing Recovery / 289
10.5.3.4 Sampling / 290
10.5.4 Symbol Decision Element / 290
10.5.5 Decoder / 292
10.6 SNR, Es/N0, and Eb/N0 / 293
10.6.1 General Definition / 293
10.6.2 Values at Sampler Output / 294
10.7 Summary of Signal Distortion Sources / 295
Appendix 10.A / 297
10.A.1 Sketch of Proof that Pulse Transform and Signal Spectrum Are Related / 297
References / 298
11 COMMUNICATIONS LINK 299
11.1 Introduction / 299
11.2 End-to-End C/N0 / 300
11.3 Signal Power on Link / 301
11.3.1 Introduction / 301
11.3.2 Loss and Variation from Payload Antenna Pointing Error / 303
11.3.3 Free-Space Loss / 303
11.3.4 Loss and Variation from Atmospheric Attenuation / 303
11.3.5 Atmospheric Effects for Carrier Frequencies from 1 to 10 GHz / 304
11.3.6 Atmospheric Effects for Carrier Frequencies Above 10 GHz / 305
11.3.6.1 Rain Attenuation / 305
11.3.6.2 Other Atmospheric Effects and Combined Effects / 308
11.3.7 Loss and Variation from Antenna Polarization Mismatch / 310
11.4 Noise Level on Link / 311
11.5 Interference on Link / 312
11.5.1 Introduction / 312
11.5.2 Adjacent-Channel Interference / 313
11.5.3 Sidelobe Interference / 314
11.5.4 Cross-Polarized Interference / 315
11.6 Link Budget / 317
References / 318
12 PROBABILISTIC TREATMENT OF MULTIBEAM DOWNLINKS 321
12.1 Introduction / 321
12.2 Multibeam-Downlink Payload Specifications / 322
12.3 Repeater-Caused Variation of C and C/Iself and Nominal Value / 324
12.3.1 Introduction / 324
12.3.2 Variation Contributions from CAMP / 326
12.3.2.1 CAMP Settability Resolution / 326
12.3.2.2 CAMP Temperature Compensation / 327
12.3.2.3 CAMP Maximum-Power Variation Due to Aging and Radiation / 327
12.3.3 Variation and Nominal-Value Contributions from TWTA / 327
12.3.3.1 Pout Nominal Value from Temperature / 327
12.3.3.2 Pout Variation Due to Aging and Radiation / 328
12.3.4 Measurement Uncertainty in Pout / 328
12.3.5 Variation Contribution from OMUX / 329
12.3.6 Variation Contribution from Other Post-TWTA Hardware Besides OMUX / 330
12.3.7 Summary of Repeater Units’ Variation and Nominal-Value Contribution / 330
12.3.8 Repeater-Caused Variation and Nominal Value of C and C/Iself / 331
12.3.8.1 Repeater-Caused C Variation and Nominal Value / 331
12.3.8.2 Repeater-Caused C/Iself Variation and Nominal Value / 333
12.4 Combining Antenna-Caused Variation into Repeater-Caused Variation / 333
12.4.1 Contribution from Antenna-Gain Inaccuracy / 334
12.4.2 Contribution from Antenna-Pointing Error / 334
12.4.3 Payload-Caused C Variation / 335
12.4.4 Payload-Caused C/Iself Variation / 336
12.5 Payload-Caused Variation of C/(IþN) / 337
12.6 Combining Atmosphere-Caused Variation into Payload-Caused Variation / 337
12.7 Optimizing Multibeam-Downlink Payload Specified on Link Availability / 339
Appendix 12.A / 340
12.A.1 Iteration Details for Optimizing Multibeam Payload Specified on Link Availability / 340
12.A.1.1 Approximate Rain-Attenuation Function and Its Inverse / 340
12.A.1.2 Atmospheric Attenuation Function and Its Inverse / 341
12.A.1.3 Details of Iteration / 341
12.A.2 Pdf of Diurnal Variation in Delta of East and West Panel Illumination / 342
References / 342
13 END-TO-END COMMUNICATIONS SYSTEM MODEL WITH FOCUS ON PAYLOAD 343
13.1 Introduction / 343
13.2 Considerations for Both Software Simulation and Hardware Emulation / 344
13.2.1 System Model / 344
13.2.2 Know the Whole Communications System / 345
13.2.3 What Results Modeling Can Provide / 346
13.2.4 Generating Symbol Stream Plus Noise / 346
13.2.5 Modeling Other Signals Present / 347
13.2.5.1 Applying Central Limit Theorem / 348
13.2.5.2 Approximating Sinewave Interferer by Noise-Like Interferer / 349
13.2.5.3 Approximating Modulated-Signal Interferer by Noise-Like Interferer / 350
13.3 Additional Considerations for Simulation / 352
13.3.1 Pitfalls of Simulation / 352
13.3.2 System Model Specialized to Simulation / 354
13.3.3 When a Signal Distortion Can Be Ignored / 354
13.3.4 Simulating Additive Noise / 355
13.3.5 Simulating Other Parameters That Vary / 356
13.3.6 HPA Simulation / 356
13.3.7 Coding, Decoding, and Interleaving Simulation / 357
13.3.8 Basic Signal-Processing Considerations / 358
13.4 Additional Considerations for Emulation / 359
13.4.1 Emulating Uplink / 359
13.4.2 Emulating Downlink / 360
13.4.3 Matching Gain Tilt and Parabolic Phase / 361
References / 362
INDEX 363