Polarization diversity antenna array for IEEE 802.11 a/n MIMO application

A dual polarization of patch antenna array for IEEE 802.11 a/n MIMO applications are proposed and experimentally studied in this paper. The four by one patch antenna array printed on 200 mm by 70.5 mm by 0.4 mm FR4 substrate. The FR4 substrate is 2.5 mm above the metal ground plane. The patch array has two input ports for the orthogonal polarizations MIMO application. The measured efficiency and gain are 70% and 13.5 dBi for one polarization and 65% and 12.5 dBi for another orthogonal polarization in the operating band 5.18 GHz∼5.82 GHz. Although the geometry of the patch elements and power divider are complicated, the ECC (envelope correlation coefficient) is less than 0.02 for the operating band. The results from both simulation and measurement for reflection coefficient, directivity, gain, ECC, and E-/H-power pattern of ports 1 and 2 are very close.