A compact inverted-F dual-band MIMO antenna with pattern diversity for WLAN applications

A compact inverted-F dual-band multiple input multiple output (MIMO) antenna with pattern diversity is presented in this paper. Two symmetric antenna elements are laid back to back, with an interelement distance of 10mm, which is equal to the 0.08 wavelength of the lower frequency band. The antenna radiator element is designed as an inverted-F type with two branches that have lengths that are the effective quarter wavelengths of 2.45 GHz and 5.5 GHz, which are particularly compatible with the IEEE 802.11n communication standard of wireless local area network (WLAN) applications. The combination of the two antenna radiation patterns forms a characteristic pattern diversity that can be used to reduce the mutual coupling effect. Experiments of the isolation of the MIMO antenna gives a result better than -20 dB in the operating frequency bands. These results were achieved without adding a decoupled component or structure. The measurements derived from the 3-D radiation patterns of the MIMO antenna, were analyzed and used to calculate correlation coefficient of 0.35 and 0.37 at the 2.45 GHz and 5.5 GHz, respectively. The proposed MIMO antenna is small in size, simple in structure, moderate in radiation gain, appropriate in terms of radiation efficiency, and so is fully compatible with wireless communication products.