An Upper Bound for the Envelope Correlation Coefficient of Antenna Clusters

A method for finding the upper bound on the envelope correlation coefficient for an arbitrary number of antenna clusters is introduced. In the described case, the envelope correlation coefficient depends on applied feeding. The theory shows a matrix description of the problem, which overcomes the need for repeated evaluations of far-field integration for different feeding vectors. This work further presents a formula for finding the highest possible value of the envelope correlation coefficient when the feeding of one antenna cluster is fixed and only the feeding weights of the second cluster can be manipulated. The proposed theory is shown in a simple example of six parallel dipoles divided into three antenna clusters.