Comparisons of different methods to determine correlation applied to multi-port UWB eleven antenna

In this paper, we compare different methods to determine correlation. First, we did analytical study on correlation of two parallel dipoles. We present two methods for analytical correlation calculation. In addition, the effect of source impedances is also studied. It is found that these two analytical methods result in the same correlation, and that source impedance matched to embedded element impedance gives the smallest correlation. Then, we compared different methods of determining correlations of multi-port antennas from measurements. Wideband eleven antenna was used for measurements. It is shown that correlation can be determined correctly either using embedded radiation far field functions based on anechoic chamber (AC) measurement (i.e., embedded far field method), or using cross-correlation definition based on reverberation chamber (RC) measurement (i.e., RC method). Scattering parameters (S-parameter) can only be used to determine correlation of lossless multi-port antenna (i.e., S-parameter method). It is also shown that for general lossy antenna, RC method is most convenient to use