Correlation coefficient expression by S-parameters for two omni-directional MIMO antennas

This paper derives a new expression of the correlation coefficient for two omni-directional antennas in terms of the easy-to-measure S-parameters. The omni-directional antennas can be monopole or dipole antennas and they are aimed for use in MIMO communication systems whose capacity performance is significantly affected by signal correlation. With this new expression, it can greatly reduce the computational complexity of antenna correlation calculations since the embedded radiation patterns of the antennas are no longer necessary. Numerical calculations demonstrate the accuracy and efficiency of the new formula.