Branch correlation measurements and analysis in an indoor Rayleigh fading channel for polarization diversity using a dual polarized patch antenna

Spatial diversity techniques are advantageous if the received signals of the diversity branches are sufficiently uncorrelated. Theoretical study using the power unbalance between the two branches employing Laplacian direction of arrival (DOA) distribution is carried out. It is shown that for low value of cross-polarization power ratio (XPR) the correlation has a negligible effect. In order to validate the theoretical results indoor NLOS measurements were carried out. The measurements were done to study the cross-correlation between two received signals of orthogonal polarization using a dual linear polarized patch antenna. The antenna has been designed, built and measured. The results of the channel measurements are given. It is concluded that received signals with orthogonal polarization in indoor Rayleigh fading channels have no significant envelope correlation.