Development of Coherent Detector Technologies for Sub-Millimetre Wave Astronomy Observations (eBook)

After completing the Bachelor degree in Electrical and Electronic Engineering in 2001, Boon Kok Tan was offered a postgraduate position in Solar Engineering, and was awarded the Master degree in 2002. Following a lecturing career at Tunku Abdul Rahman University in Kuala Lumpur, he was offered a D. Phil position – funded by the prestigious King of Malaysia awards – at Oxford Astrophysics to work on the development of quantum limited coherent detectors for submillimetre astronomy. B. K. Tan obtained the D. Phil degree at Oxford in 2012. He is currently a member the Millimetre Detectors group of Oxford Astrophysics, leading the development of coherent THz detectors for the Atacama Large Millimetre Array (ALMA) and collaborates also with the Wawasan Open University, Malaysia. Dr. Tan was awarded the 2014 MERAC Prize by the European Astronomical Society for the Best Doctoral Thesis in the category "Technologies".

Supervisor’s Foreword 6
Preface 9
Abstract 16
Acknowledgments 17
Contents 18
1 Introduction 22
1.1 Sub-Millimetre Astronomy 23
1.2 Sub-Millimetre Telescopes 25
1.2.1 ALMA 26
1.3 Sub-Millimetre Wave Detection 27
1.3.1 SIS Junctions as Heterodyne Mixers 28
1.3.2 SIS Heterodyne Receivers 28
1.3.3 Mixer Feeds 30
1.4 Current State of SIS Mixers 33
References 34
2 Multiple Flare-Angle Smooth-Walled Horn 36
2.1 Introduction 36
2.2 Feed Horn Design 38
2.2.1 Genetic Algorithm 41
2.2.2 700GHz Multiple Flare-Angle Horn 42
2.3 Horn Fabrication 44
2.4 Experimental Setup 45
2.5 Measurement Results and Analyses 46
2.6 Study of Multiple Flare-Angle Horn Using Ansys HFSS 50
2.6.1 Comparing Simulation Results with Modal Matching 50
2.6.2 Tolerance Analysis 53
2.6.3 Cross-Coupling Between Two Adjacent Horns 54
2.7 Summary 56
References 56
3 SIS Mixer Theory 58
3.1 Introduction 58
3.2 Quasiparticle Tunnelling 59
3.2.1 Photon-Assisted Quasiparticle Tunnelling 61
3.3 Cooper Pair Tunnelling 62
3.3.1 Fiske Steps and Shapiro Steps 63
3.4 General Mixer Theory 64
3.4.1 Large Signal Analysis 65
3.4.2 Small Signal Analysis 66
3.4.3 Impedance Recovery 68
3.5 Measurement of the SIS Mixer Performance 70
3.5.1 Y-Factor Noise Temperature Measurement 70
3.5.2 Noise Temperature and Gain Correction for Optical Losses 74
3.6 Summary 75
References 75
4 Design of Unilateral Finline SIS Mixer 77
4.1 Introduction 77
4.1.1 Silicon-On-Insulator (SOI) Technology 78
4.2 Mixer Design 79
4.2.1 Waveguide-to-Slotline Transition 81
4.2.2 Slotline-to-Microstrip Transition 82
4.2.3 Tuning Circuit 85
4.3 Full RF Mixer Chip Simulations 87
4.4 IF Matching 88
4.5 Full Mixer Chip SuperMix Simulations 92
4.6 Summary 93
4.7 Postscript 93
References 95
5 Single-Ended Mixer Tests 96
5.1 Introduction 96
5.2 Device Fabrication 96
5.3 Mixer Assembly 99
5.3.1 Device Handling 102
5.4 Mixer Test Setup 102
5.5 Results and Analysis 104
5.5.1 Quartz Devices 105
5.5.2 SOI Devices 108
5.6 Summary 112
5.7 Postscript 113
References 115
6 Single-Chip Integrated Balanced SIS Mixer 116
6.1 Introduction 116
6.2 Design of the RF Passive Circuit Components 117
6.2.1 RF Quadrature Hybrid 119
6.2.2 DC/IF Block 120
6.2.3 IF Hybrid 121
6.3 Balanced Mixer Simulations 122
6.4 Device Fabrication 124
6.5 Experimental Setup 126
6.5.1 Mixer Assembly and Device Mounting 128
6.6 Results and Analysis 130
6.6.1 Measured Performance of the RF Hybrid and the DC/IF Block 131
6.6.2 Balanced Mixer Performance 132
6.6.3 Single Junction Noise Temperature 138
6.7 Summary 140
References 141
7 Design of 700 GHz Single Sideband SIS Mixers 143
7.1 Introduction 143
7.1.1 Sideband Separating Mixer 143
7.1.2 Balanced with Sideband Separating Mixer 145
7.2 Design of the RF Passive Circuit Components 146
7.2.1 In-Phase Power Divider 147
7.2.2 --15dB LO Directional Coupler 148
7.2.3 4K Termination Cold Load 149
7.3 Mixer Simulations 150
7.3.1 Sideband Separating Mixer 150
7.3.2 Balanced-2SB Mixer Design 152
7.4 Summary 153
References 154
8 The Characteristics of an SIS Junction Near Its Superconducting Gap 155
8.1 Local Tunnelling Heating Effect in SIS Junction 155
8.1.1 Method of Analysis 156
8.1.2 Results and Discussion 159
8.2 Josephson Effects on the Sensitivity of an SIS Mixer 160
8.2.1 Josephson Current Enhancing SIS Mixer Performance 161
8.3 Summary 163
References 163
9 Generation of Local Oscillator Signal via Photomixing 165
9.1 Introduction 165
9.1.1 Optical Heterodyning 166
9.2 Generation of Local Oscillator Signal 167
9.2.1 Photomixer and System Setup 167
9.2.2 Infrared Lasers 169
9.2.3 Pumping an SIS Mixer with a Photonic LO Source 170
9.3 Frequency Stabilisation Schemes 171
9.4 Summary 173
References 173
10 CO(3rightarrow2) Observations of NGC 2976 and NGC 3351 175
10.1 Introduction 175
10.2 Target Galaxies 178
10.2.1 Archival Data 178
10.3 Observations and Data Reduction 179
10.3.1 Data Reduction 180
10.4 Results and Discussion 182
10.4.1 R31 Line Ratio 186
10.4.2 Molecular Gas Mass Estimation 190
10.4.3 Correlation with PAH Emission 194
10.5 Summary 198
References 199
11 Concluding Remarks 203
11.1 Toward Multi-pixel Focal Plane Array Receivers 205
References 206
Appendix A Ancillary Data of Individual Tested Device 207
Appendix B Ancillary Data of Individual Tested BalancedDevice 214
Appendix C List of All Beam Patterns Measured Up to Date 218
Appendix D 230GHz Scalable Design 221
Index 227