Space Efficiency of Multiple Element Antennas

Multiple element antennas (MEAs) support multiple-input multiple-output (MIMO) communications and other antenna diversity techniques, resulting in better communications performance than available from single antenna systems. The space occupied by MEAs becomes important when the antennas are integrated into small or portable devices, and a metric would be helpful for the design of compact MEAs. A figure of merit for the spatial efficiency is presented here for evaluating the MEA compactness with respect to the MEA bandwidth and the potential communications performance. A spherical volume is used and different propagation scenario models can be incorporated. The impact of element efficiencies, mutual coupling, correlation, diversity scheme, and propagation scenario are included.