Representation of the envelope correlation as a function of distance and frequency for a two-port antenna system

Space diversity is a well-known technique to improve signal quality in a mobile communication system. The envelope correlation for closely spaced antennas has been shown to be low enough to make this diversity technique possible for implementation in mobile handsets. The correlation between signals received by different antennas needed to design good space diversity systems can be calculated from the antenna radiation patterns and also from S-parameters. Two monopoles are used as an example. The envelope correlation of a two-port antenna system obtained by computer simulation is compared with measurements. It is shown that the approach to calculate envelope correlation using S-parameters can be considered as a good approach.