The current spectrum crunch calls for innovative approaches to utilize the available frequency spectrum more efficiently. This proposal aims at addressing this issue by introducing a new class of antenna arrays called coupled antenna arrays (CAAs). The unique nature of the CAAs allows for placing the antenna elements closely resulting in very small arrays that are suitable for mobile radios. The performance of CAAs should be assessed with proper models and analysis tools. Also, utilizing CAAs for different applications requires proper signal processing techniques. The proposed research is expected to result in achieving performance levels and spectrum efficiencies that far exceed the current wireless technologies. In the short term, the expected research findings will lead to the development of multi-antenna receivers with offered spectral efficiencies that cannot be easily achieved using any other existing technology today. This will profoundly impact the efficiency of spectrum utilization of future wireless systems. In the long term, these concepts are expected to revolutionize how we solve problems in a variety of areas ranging from wireless communications and signal processing to antenna theory and radar systems. In addition to these positive societal, economic, and technological impacts, the proposed work integrates research and education through a carefully planned series of activities. These will facilitate the engineering-oriented professional development of K-12 science teachers; integrate research activities into the teaching of science/engineering at the K-12, undergraduate, and graduate levels; improve recruitment and retention of under-represented minority and female students in research activities at the pre-college, undergraduate, and graduate levels; and result in development and broad dissemination of research based educational materials through both traditional and non-traditional means of dissemination.
The overall objective of the proposed interdisciplinary research project is to use recent advances in the areas of multi-antenna wireless communication systems and signal processing and coupled antenna array (CAA) technology to fundamentally enhance the efficiency of spectrum utilization of mobile wireless communication systems. Specifically, the PI and the Co-PI plan to develop a new class of electrically-small CAAs and investigate their applications for: 1) Spectrum co-existence and capacity enhancement of wireless systems operating in strong interference environments; 2) Capacity-enhancement of multi-input multi-output (MIMO) communications systems; and 3) Capacity enhancement and complexity reduction of multi-cell cooperative networks. The proposed work bridges the gaps between two traditionally separate areas of research to develop viable solutions for enhancing the spectrum efficiency of future wireless systems. This work particularly emphasizes on small mobile wireless devices that cannot accommodate large antenna arrays, and work at frequencies below 5.0 GHz where the propagation conditions are most suitable for achieving wide-area coverage that many mobile wireless systems rely on. This project involves two fundamental thrusts of investigation that are expected to significantly advance our knowledge and understanding in the fields of applied electromagnetics/antenna design and communications/signal processing. The first involves developing a new class of CAAs that offer significantly higher directivities and signal-to-noise ratios over conventional antenna arrays, particularly when the overall electrical dimensions of the array are small. Investigating the architectures, performance, capabilities, and limitations of the proposed CAA concept is expected to fundamentally advance our knowledge and understanding of antenna array theory and design. The second thrust involves investigating the new communications applications that the proposed CAAs enable. CAAs introduce fundamentally new capabilities to small-aperture, mobile wireless devices that are not available using any other existing technology today. These capabilities will be exploited to increase the frequency as well as directional selectivity of small antenna arrays, enhance the capacity of MIMO wireless systems, mitigate the adverse effects of interference in congested spectral environments, and reduce the complexity and increase the spectral efficiency of cellular networks.
