A Six-Port MIMO Antenna System With High Isolation for 5-GHz WLAN Access Points

A six-port multiple-input–multiple-output (MIMO) antenna system with high port isolation for 5-GHz WLAN access points application is proposed in this letter. It consists of three vertically polarized and three horizontally polarized antenna elements alternately mounted on a pyramidal metal structure. Several techniques are used to improve the isolation performances of the antenna system, including the aperture-coupled feeding mechanism, quarter-wavelength chokes, and parasitic grooves. Measured results show that more than 45 dB isolation can be obtained between any two elements of the system within the operating band.