Dual-Band Dual-Polarized Compact Log-Periodic Dipole Array for MIMO WLAN Applications

A compact dual-band dual-polarized log-periodic dipole array with a dimension of 160 ×160 ×60 mm³ for multiple-input-multiple-output (MIMO) WLAN applications is proposed. In this antenna, there are 12 antennas: six for horizontal polarization and six for vertical polarization. In order to achieve dual linear polarizations and beam switching, six horizontal antennas are placed in sequential, rotating arrangement on a horizontal substrate panel with an equal inclination angle of 60^° to form a symmetrical structure, while the other six antennas for vertical polarization are inserted through slots made on the horizontal substrate panel. Furthermore, six pairs of double T-type slits are introduced to mainly reduce the mutual coupling between the horizontal antennas. The proposed array is manufactured and exhibits the characteristics of high isolation, good front-to-back ratio, and average gains of 5 and 6 dBi over the 2.4- and 5-GHz band, respectively. The MIMO performance of the array is analyzed and evaluated by mutual coupling and the envelope correlation coefficient.