Array of Eight Circularly Polarized Microstrip Antennas for IEEE 802.11ac MIMO WLAN

An array of eight circularly polarized microstrip antennas is proposed as MIMO antennas for IEEE 802.11ac MIMO WLAN system. The proposed antenna design is implemented at access point side. The eight antennas are split into two groups of four antennas. The antennas belong to the same group are set with the same polarization while the antennas belong to the first group have different polarization from the one of the antennas in the second group. This array of antennas having two different polarization has been investigated. The results show that setting the adjacent elements with different polarizations, such as right-hand and left-hand circular polarizations, allows the suppression of the mutual coupling between antennas. The highest mutual coupling is -26.8 dB. Each antenna element covers 480 MHz bandwidth. We calculate and estimate the MIMO capacity that is supported by the antenna. It can be shown that 1 Gbps capacity can be reached using the proposed antennas configuration.