A Directional Single Beam MIMO Antenna with 2-Transmitters and 2-Receivers for WLAN System

A $2\times 2$ MIMO antenna with single beam and high gain has been suggested, which is suitable for WLAN applications operating at 2.4 and 5.8 GHz. The lower-band unit consists of four rectangular slots, a hat-shaped slot and two centrally symmetrical slots, respectively. It adjusts the impedance matching by controlling their length and width. The upper-band unit realizes strong current coupling through the gap between the main radiation patch and the four L-shaped parasitic patches. Besides, the parasitic patches are arranged around the radiating patch to expand the bandwidth. By assembling the units of the dual bands together, a 2×2 array with high gain is formed, covering the WLAN frequency band. Experimental results show that a dual bandwidth of 2.38-2.68 GHz and 4.74-6.61 GHz, covering the common WLAN frequency bands that include 2.4-2.485 GHz and 5.15-5.85 GHz can be achieved. Besides the high isolation, the antenna can also obtain high gain and directional radiation characteristics at low cost. Therefore, the antenna possesses the capability to be extensively utilized in contemporary communication systems.