Spatial correlation of half-wavelength dipole arrays using spherical mode expansion

The performance of multiple-input multiple- output (MIMO) systems strongly depends on the correlation between antenna elements. An analytical expression is given for the 3D spatial correlation (SC) coefficient of half-wavelength (¿/2) dipole antennas by using spherical mode expansion of plane waves. The mutual coupling (MC) effect is also considered using the concept of coupling matrix. Our results show that azimuth spread (AS) is the primary determinant of the SC of horizontally separated dipole antennas. The effect of MC on SC depends on the interelement spacing and richness of scattering.