Effect of Polarization Diversity on Envelope Correlation Coefficient of Multiple-Input Multiple-Output Multiband Antenna

This paper investigates the effect of polarization diversity on the configuration of a $2 \times 2$ multiple-input multipleoutput (MIMO) multiband antenna by determining the envelope correlation coefficient (ECC). The proposed multiband antenna is expected to fulfill wireless communication systems requiring high channel capacity and low interference. Its radiating elements take the official HALAL logo shape, in which both linearly and orthogonally polarized configurations are explored. The investigation results show that the orthogonally polarized configuration yields significantly lower ECC compared to the linearly polarized configuration. At the frequency of 2.4 GHz, the ECC for orthogonally polarized configuration with an inter-element distance of 10 mm achieves a reduction of approximately $\mathbf{6 4 \%}$ compared to the one for linearly polarized configuration. The reduction in ECC demonstrates better performance in minimizing mutual coupling between antenna elements, thereby improving the efficiency and capacity of wireless communication systems.