Multiplexing index and MIMO band index: Two novel metrics for MIMO antenna evaluation

The paper presents two new figures of merit that efficiently evaluate the performance of a MIMO terminal, namely the spatial multiplexing index (SMI) and the MIMO band index (MBI). Both metrics incorporate the impact of the antenna efficiency, efficiency imbalance and the spatial correlation of the antenna terminal into its spatial multiplexing performance. The SMI is introduced as a “green” index that expresses the minimum SNR required by the MIMO terminal in order to support spatial multiplexing. The MBI metric completes the picture regarding the MIMO antenna characterization by taking into account the wideband performance of the antenna-under-test and thus is particularly useful for antenna engineers whose goal is to achieve the optimum MIMO antenna system design over a desired frequency band.