High Resolution Passive Imaging Using III-V Monolithic Millimetre Integrated Circuits (MMICs) Operating at 200GHz

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This is a joint University of Glasgow, QinetiQ project in millimetre-wave imaging, primarily for safety and security applications - an excellent example of academia and industry working together to realise an operational, next generation, leading edge, functional prototype imaging system. The University of Glasgow is a world leading Centre in nanofabrication technology and millimetre-wave component design. Qinetiq is an internationally leading UK high technology company with particular specialism in producing advanced imaging systems.Millimetre-wave radar and imaging systems which operate in the 100-300 GHz frequency range, have numerous applications. Unlike infrared, millimetre-waves can penetrate fog, dust, smoke and light rain which makes them suitable for target acquisition, aircraft navigation, landing in zero visibility conditions and in unmanned autonomous aircraft.Millimetre-waves are able to passively detect concealed plastic and metal objects under clothing making them ideal for mass transportation security applications. In addition, the investigation of chemical and biological phenomena with non-ionising millimetre and terahertz waves may lead to compact detectors of dangerous substances and will enable new opportunities in medical diagnostic tools. Further, the ability of millimetre-waves to penetrate through few centimetres of sand render them capable of remote sensing and landmine clearing operation.The key to imaging and sensing systems operating at frequencies above 100 GHz is the realisation of ultra-high sensitivity Monolithic Millimetre-wave Integrated Circuits (MMIC's) in which low noise amplifiers (LNA's), detectors and antennas are combined on a single semiconductor chip. The function of the LNA is to amplify the received signal from the antenna, keeping the background noise at low level. The diode detector transforms the signals received into pixels with different shading intensities, and hence reconstructing a real image as the antenna scans across the target.Direct detection techniques have primarily been demonstrated only at frequencies below 100GHz, due to the performance limitations of current nano technologies and the largely unexplored design challenges at mm-wave frequencies beyond 100GHz. The advantages for implementing mm-wave frequencies beyond 100GHz are; higher resolution imaging, reduce cluttering, and smaller component size; hence a higher image definition, fewer false alarms, increasing safety factor, reduced cost, and less bulky systems can be realised. MMIC design for the applications mentioned above at millimetre-wave frequencies beyond 100 GHz, and specifically, next generation imaging systems operating at 200 GHz, presents major challenges in both technology and design. In technology, transistors with critical dimensions of 50nm (0.001x the diameter of a human hair), and three dimensional nano structures are required. In integrated circuit design beyond 100 GHz, all components produced on the chips are highly sensitive to their surroundings, including parasitic effects, so that every last FemtoFarad of capacitance an Ohm of resistance has to be considered. To insure a successful outcome, the overall project has been broken down into a number of tasks, each of which will be verified independently. The final prototype imaging system operating at 200GHz will be assembled and tested as a joint effort between the University of Glasgow and QinetiQ, both of whom are well established and internationally recognised research groups with the required technology and design expertise to successfully produce the demonstrator system. This project will allow the realisation of more compact, higher imaging resolution systems, paving the way for the next generation of single element and array imaging systems on a single chip.