Development of coherent detector technologies for sub-millimetre wave astronomy observations : doctoral thesis accepted by University of Oxford, Oxford, UK

The thesis describes the development of receiver technologies for sub-millimetre astronomy instruments, focusing on high performance coherent cryogenic detectors operating close to the superconductor gap frequency. The mixer chip which comprises the SIS devices, fed by a unilateral finline and matching planar circuits was fabricated on 15 micron silicon substrate using the recently developed Silicon-On-Insulator (SOI) technology. This offered broadband IF and RF performance, with fully integrated on-chip planar circuits resulting in an easily reproducible mixer chip and a simple mixer block. An important consequence of this design is that it can be extended to the supra-THz region and making the fabrication of multi-pixel heterodyne arrays feasible. The extension of the operation of major telescopes such as ALMA, APEX and the GLT from single pixel to large format arrays is the subject of extensive research at present time since it will allow fast mapping combined with high resolution of the submillimetre sky. The technology described in this thesis makes a major contribution to this effort. Front Matter....Pages i-xxiv Introduction....Pages 1-14 Multiple Flare-Angle Smooth-Walled Horn....Pages 15-36 SIS Mixer Theory....Pages 37-55 Design of Unilateral Finline SIS Mixer....Pages 57-75 Single-Ended Mixer Tests....Pages 77-96 Single-Chip Integrated Balanced SIS Mixer....Pages 97-123 Design of 700 GHz Single Sideband SIS Mixers....Pages 125-136 The Characteristics of an SIS Junction Near Its Superconducting Gap....Pages 137-146 Generation of Local Oscillator Signal via Photomixing....Pages 147-156 CO \({}_{(3\rightarrow 2)}\) Observations of NGC 2976 and NGC 3351....Pages 157-184 Concluding Remarks....Pages 185-188 Back Matter....Pages 189-219