Electronically beam-steerable array antennas (phased arrays or smart antennas) at microwave and millimetre-wave (mm-wave) frequencies are extremely important for various wireless systems including satellite communications, terrestrial mobile communications, radars, "Internet Of Things", wireless power transmission, satellite navigations and deep-space communication. Traditionally, beam steering of antenna is achieved by moving the reflector mechanically, which is slow, bulky and not reliable. Phased arrays, which integrate antennas and phase shifter circuits, are an attractive alternative to gimbaled parabolic reflectors as they offer rapid beam steering towards the desired targets and better reliability. Phase shifters are critical components in phased arrays as the beam steering is achieved by controlling phase shifters electronically. A promising research direction to create small, fast, reliable phase shifters with low insertion loss at high frequency is the use of tunable dielectric materials due to its potential of monolithic fabrication of array antennas and circuits. A breakthrough in such materials came recently when we demonstrated that Lead Niobate Pyrochlores PbnNb2O5+n gives the best combination of dielectric constant, tunability and low loss of any known thin film system. Translating these superior materials properties into actual device performance and high-performance electronically beam-steerable arrays antennas at microwave and mm-wave bands are the key aims of this project

We are living through a revolution, as electronic communications become ever more ubiquitous in our daily lives. The use of mobile and smart phone technology is becoming increasingly universal, with applications beyond voice communications including access to social and business data, entertainment through live and more immersive video streaming and distributed processing and storage of information through high performance data centres and the cloud. All of this needs to be achieved with high levels of reliability, flexibility and at low cost, and solutions need to integrate developments in theoretical algorithms, optimization of software and ongoing advances in hardware performance. These trends will continue to shape our future. By 2020 it is predicted that the number of network-connected devices will reach 1000 times the world's population: there will be 7 trillion connected devices for 7 billion people. This will result in 1.3 zettabytes of global internet traffic by 2016 (with over 80% of this being due to video), requiring a 27% increase in energy consumption by telecommunications networks. The UK's excellence in communications has been a focal point for inward investment for many years - already this sector has a value of £82Bn a year to the UK economy (~5.7% GDP). However this strength is threatened by an age imbalance in the workforce and a shortage of highly skilled researchers. Our CDT will bridge this skills gap, by training the next generation of researchers, who can ensure that the UK remains at the heart of the worldwide communications industry, providing a much needed growth dividend for our economy. It will be guided by the commercial imperatives from our industry partners, and motivated by application drivers in future cities, transport, e-health, homeland security and entertainment. The expansion of the UK internet business is fuelled by innovative product development in optical transport mechanisms, wireless enabled technologies and efficient data representations. It is thus essential that communications practitioners of the future have an overall system perspective, bridging the gaps between hardware and software, wireless and wired communications, and application drivers and network constraints. While communications technology is the enabler, it is humans that are the producers, consumers and beneficiaries in terms of its broader applications. Our programme will thus focus on the challenges within and the interactions between the key domains of People, Power and Performance. Over three cohorts, the new CDT will build on Bristol's core expertise in Efficient Systems and Enabling Technologies to engineer novel solutions, offering enhanced performance, lower cost and reduced environmental impact. We will train our students in the mathematical fundamentals which underpin modern communication systems and deliver both human and technological solutions for the communication systems landscape of the future. In summary, Future Communications 2 will produce a new type of PhD graduate: one who is intellectually leading, creative, mathematically rigorous and who understands the commercial implications of his or her work - people who are the future technical leaders in the sector.

Future generation (5G) mobile phones and other portable devices will need to transfer data at a much higher rate than at present in order to accommodate an increase in the number of users, the employment of multi-band and multi-channel operation, the projected dramatic increase in wireless information exchange such as with high definition video and the large increase in connectivity where many devices will be connected to other devices (called "The Internet of Things"). This places big challenges on the performance of base stations in terms of fidelity of the signal and improved energy efficiency since energy usage could increase in line with the amount of data transfer. To meet the predicted massive increase in capacity there will be a reduced reliance on large coverage base-stations, with small-cell base-stations (operating at lower power levels) becoming much more common. In addition to the challenges mentioned above, small cells will demand a larger number of low cost systems. To meet these challenges this proposal aims to use electronic devices made from gallium nitride (GaN) which has the desirable property of being able to operate at very high frequencies (for high data transfer rates) and in a very efficient manner to reduce the projected energy usage. To maintain the high frequency capability of these devices, circuits will be integrated into a single circuit to reduce the slowing effects of stray inductances and capacitances. Additionally these integrated circuits will be manufactured on large area silicon substrates which will reduce the system unit cost significantly. The proposed high levels of integration using GaN devices as the basic building block and combining microwave and switching technologies have never been attempted before and requires a multi-disciplinary team with complementary specialist expertise. The proposed consortium brings together the leading UK groups with expertise in GaN crystal growth (Cambridge), device design and fabrication (Sheffield), high frequency circuit design and fabrication (Glasgow), variable power supply design (Manchester) and high frequency characterisation and power amplifier design (Cardiff). Before designing and developing the technology for fabricating the integrated systems to demonstrate the viability of the proposed solutions, a deep scientific understanding is required into how the quality of the GaN crystals on silicon substrates affect the operation of the devices. In summary, the powerful grouping within the project will bring together the expertise to design and produce the novel integrated circuits and systems to meet the demanding objectives of this research proposal.

Abstracts are not currently available in GtR for all funded research. This is normally because the abstract was not required at the time of proposal submission, but may be because it included sensitive information such as personal details.

Label-free detection of circulating tumour cells (CTCs) is considered to be one of the holy grails of biosensing. CTCs are malignant cells shed into the bloodstream from a tumour, which have the potential to establish metastases. The separation and subsequent characterization of these cells is of vital importance for cancer diagnosis and development of personalized cancer therapies. Biochemical CTC separation methods have proven to be highly inefficient and, therefore, preventive screening by sole blood analysis is currently not reliable. Microwave-to-terahertz dielectric measurements were successfully used for the identification of cancer cells; their capability for tumour tissue imaging is clinically established as a viable alternative to X-rays and MRI. The frequency range from 10 GHz up to about 1 THz is extremely promising for the detection of single tumour cells. Due to the diminishing cell membrane polarization effects, the cell membrane becomes transparent, but cell scattering is still negligible, in contrast to that found in the visible and near/medium-infrared range. Due to the high electromagnetic absorption of water up to about 1 THz, electromagnetic resonators with high quality factors and highly concentrated electric field within a small integrated microfluidic reservoir (previously demonstrated by the team), which essentially contains one cell at a time, represent an ideal system for fast and accurate dielectric measurements. This is because the single cell lies within their natural liquid environment. In order to tackle the problem of extremely low abundance of CTCs in blood samples, we intend to combine microfluidic separation techniques with integrated microwave-to-terahertz resonators on one chip or as a multichip combination, aiming towards a lab-on-chip approach for clinical applications. In order to achieve this ambitious goal, within this three-year project, we suggest a multidisciplinary approach, based on the expertise of the associated members of Imperial's Centre for Terahertz Science and Engineering (made up of academics and researchers from the Depts. of Materials, Electrical and Electronic Engineering and Physics), along with selected groups from dedicated areas of Life Sciences (which includes cancer cell biology and cell biosensing), plus the expertise of oncologists from Imperial's Faculty of Medicine. A variety of tumour cell suspension of defined concentration based on whole blood, serum or water being derived from a murine model will be our gold standard approach for the generation of a database of dielectric properties of different types of tumour cells, for the optimization of different sensor chip approaches, and for the development of cell detection methods. As a key milestone, towards the end of the project, we will demonstrate CTC detection in human blood samples. As the main engineering challenge of this project, three different electromagnetic resonator approaches will be investigated, based on our previous work on silicon MEMS technology for nanolitre liquid measurements: dielectric resonators, photonic crystals and spoof plasmon-based metamaterials. Advanced micro- and nano-machining techniques like deep reactive ion etching, e-beam lithography and focussed ion-beam etching will be employed for the manufacturing of fully-integrated (sub-) THz resonator-microfluidic systems. On the way towards the grand challenge of CTC detection, we intend to investigate two potential applications, which may generate clinical impact on a shorter timescale: Label-free detection of leukaemia cells within a murine model and bladder cancer cell detection in human urine samples. In both cases, the expected cell abundance is much higher than in the case of CTC, but the methods of dielectric cell recognition are identical to CTC detection. Follow-up projects including clinical studies plus stronger involvement of industry are likely to be launched during the time-span of this project.