Aerial Degrees of Freedom of Parasitic Arrays for Single Rf Front-end Mimo Transceivers

The beamspace domain of parasitic antenna arrays is explored in this paper, providing the aerial degrees of freedom available for use in Multiple Input-Multiple Output (MIMO) systems. The beamspace representation allows for the design of an alternative MIMO architecture based on single radio-frequency (RF) chains, and facilitates the inclusion of MIMO transceivers in devices with strict size limitations. A three dimensional orthogonal expansion is performed on the beamspace domain providing the basis patterns used for mapping of the transmitted symbols and for sampling at the receiver. The expansion is based on the Gram-Schmidt orthonormalization procedure and can be generalized for any parasitic antenna array. The multiplexing capability of ESPAR antennas is presented as a means for supporting future performance demanding communication systems. Performance evaluation results are illustrated in detail.