Research is an activity that identifies and develops new capabilities. It ranges from the conception of completely novel ideas, through feasibilities studies and demonstrators, to incremental improvements to mission proven systems.
The maturity of any research can be benchmarked by a step on the Technology Readiness Level (TRL) scale. These steps have strict definitions; the scale ranges from TRL1 for novel conception to TRL8 for mission proven systems. Lower TRL research is conducted usually by universities and research centres. Higher TRL research is carried out by commercial companies, sometimes outsourced to other institutes.
Public sources of funding can be available for funding research between TRL1 and TRL4. Companies normally fund TRL of six and above, when low-risk routes to market are identified. Total costs involved in transiting a step on the TRL scale increase by an order of magnitude for each step.
Projects below build on peer reviewed work to date and on-going dynamic research activities, driving forward technology and techniques on a number of fronts simultaneously. Projects may run from short 3-month contracts to PhD studentships.
Investigate the feasibility of full polarimetric radar technologies to screen individuals at distances of tens of metres for concealed threats. This active technique (whereby a coherent electromagnetic wave is transmitted to the subject and the reflection measured) enables a greater information content to be extracted than with a polarimetric passive system. This is critical in a regime where the spatial information content (limited by diffraction) is low and where the passive signature from threats is very much smaller than the background emission. Excitation by coherent waves probes the target in a polarimetric vector space, at a number of different frequencies, transmitting this information back to the transceiver for analysis. This will revolutionise the way stand-off security screening is performed at checkpoints and in public places for protection of the general public.
Investigate aperture synthesis image generation algorithms for three-dimensional imaging of subjects in walk-through, high-performance airport security screening portals. The field-of-view and depth-of-field is unlimited using this technique. Radiometric aperture synthesis (a technique from radio astronomy) has the capability to deliver artefact free, machine interpretable imagery of threats concealed in areas of the body that are normally difficult to screen using conventional coherently illuminating millimetre wave systems.
Being able to identify non-metallic threats concealed anywhere on the human body, rapidly and efficiently, is ideal for airport security and will lead to spin out products for other deployment scenarios (e.g. entrances to public transport systems, buildings, arenas etc.). The measured signature, being a combination of known reflectance and thermal emission from the human body, means this screening technique is virtually impossible to defeat. The system hardware for aperture synthesis imagers will he heavily dependent on millimetre wave receivers linked to FPGA based digital cross-correlators. Aperture synthesis image creation algorithms can be investigated using existing validated forward simulation software, whilst hardware for portals is developed in parallel.
Investigate full polarimetric ray tracing algorithms and processing in GPUs to enable high-speed scene simulations, including media effects of scattering and semitransparency for active and passive imaging. Simulation scenarios are generally all-weather sensing (including brown-out), security screening (for non-metallic threats) and satellite based earth observation. Scene simulations are an excellent way of illustrating how phenomenology changes through the different atmospheric transmission (at 35, 94, 140 & 220 GHz) and absorption (at 60 & 183 GHz) windows. The analysis of much experimental imagery has demonstrated the simulation technique to be robust. Simulation provides a means of assessing imager system performance for a wide range of scenarios without having to conduct lengthy and expensive trials and experiments.
Investigate the signatures of human skin and tissue in healthy and unhealthy states and determine how these may be measured with precision for medical applications. A range of imaging and beam-forming techniques can be used to extract spatial information about the skin with resolutions down to 0.1 mm in the millimetre wave band. The capability will extend down to a depth of ~ 1 mm into the skin, with greater penetration being possible at frequencies below the millimetre wave band (< 30 GHz). Measurement with this precision over specific areas of the body, or over the whole of the human body, will be a completely novel diagnostic technique, revealing new information about the state of patients' health. It will lead to new sensing modalities in medicine, either as a stand-alone system, or in conjunction with other medical sensing techniques.
Investigate if quantum entanglement may be demonstrated in the Rayleigh-Jeans (RJ) regime, a domain where the thermal energy kT is greater than the photon energy hf. Since the 1980's entanglement has been demonstrated and researched in the in the quantum regime, that being where the photon energy is greater than the thermal energy, which means operating in the visible band, or at lower frequencies using cryogenic cooling.
The challenge is to build the ambient temperature mm-wave homodyne Bell Test interferometer and demonstrate the existence of entangled photons in the millimetre wave band, thus showing that entangled state signatures well below the level of the natural thermal noise can be detected. A source of entangled mm-wave photons for this is currently being sought by exploiting ideas developed in non-linear optics, potentially in metamaterials, ferrites and acousto-optic crystals that are non-centrosymmetric. In the mm-wave system the Bell Test statistic 'S' would be measured to determine if the Bell inequality is violated, ie local reality has been broken. Sensors based on R-J entanglement may lead the way to novel sensors in the millimetre wave band that can deliver quantum capabilities below the level of thermal noise. The technique will have applications in novel imaging, covert radar and secure communications.
Investigate how Field Programmable Gate Arrays (FPGAs) can interface to millimetre wave receivers, to sample and process data at GHz rates for aperture synthesis imaging, radar sensing and quantum applications. Short word, or single bit, digitisation at ~ 1 giga sample per second using comparators and FPGAs means electric fields of millimetre wave radiation can be processed to enable cross-correlators and phased array receivers to operate in real-time for sensing applications. Opting for short words enables large bandwidths to be realised at much reduced cost, resulting in greater sensitivities and information gathering capacities. These developments will revolutionise millimetre wave sensing capabilities, so they can be widely deployed in market driven applications of security screening and all-weather imaging and research into medical and quantum applications.