Dual Band MIMO Antenna Composed of Two Low Profile Unbalanced Fed Inverted L Antennas for Wireless Communications

A low profile dual-band multiple-input-multiple-output (MIMO) antenna system is proposed. The proposed MIMO antenna consists of two low profile unbalanced fed inverted L antennas with parasitic elements to resonate at 2.45 GHz and 5 GHz. The structure is uncomplicated by locating two ultra low profile inverted L antennas on the finite conducting plane. The proposed MIMO antenna is numerically and experimentally analyzed. When the size of conducting plane is 55 mm by 55 mm and the height of antenna is 9 mm, the directive gain of 4.11 dBi and the S11 bandwidth of 5.71% are achieved for lower frequency of 2.45 GHz. At the upper frequency of 5 GHz, the directive gain of 8.22 dBi and the S11 bandwidth of 6% are obtained. The proposed antenna has good diversity gain, shown by the correlation coefficient becomes less than 0.005 at the frequency of 2.45 GHz and 5 GHz band when the distance between inverted L elements is 41 mm. A good agreement between calculated and measured results is obtained. The results show that the weak mutual coupling of the proposed antenna and this feature enables it to cover the required bandwidths for WLAN operation at the 2.4 GHz band and 5 GHz band.