Small-size WLAN MIMO antenna array with high isolation for laptop computer application

This paper proposes an isolation technique for two small-size wireless local area network (WLAN) multiple-input multiple-output (MIMO) laptop computer antennas. The MIMO antenna array is designed to operate in the dual frequency bands covering the WLAN 2.4/5.2/5.8 GHz bands and has a small size, a low height, and a small thickness especially suitable for ultra-thin notebook computers. The size of the designed antenna array has been reduced to about 40% those of the MIMO arrays appearing in the recent literature. The designed isolation element consists of two monopole slots between the antenna radiating elements. These two monopole slots have their respective lengths of a quarter-wavelength, one at 2.45 GHz and the other at 5.5 GHz. The isolation elements block the horizontal surface currents on the system´s ground plane, leading to the reduction of the mutual coupling between the two source antennas and hence the excellent isolation between them. Results show that the proposed MIMO antenna array has good characteristics of antenna radiation efficiency, and impedance matching in the two bands of interest.