Triple-Band MIMO Antenna for Mobile Wireless Applications

This letter presents a planar triple-band multiple-input-multiple-output (MIMO) antenna that meets GSM900/1800 and LTE2600 bands protocols. The antenna element contains three individual meander-line-type inverted-L radiators; the highest frequency band radiator is fed by a transmission line, while the other two utilize the proximity-coupling feeding mechanism driven by the highest band radiator. The MIMO antenna is incorporated with two symmetric triple-band antenna elements and two physical decoupling devices. The two antenna elements are closely spaced with 1/15 wavelength of the lowest band. The two decoupling devices, a T-shaped slot and a meandering microstrip-line resonator, are built for the highest and the lowest frequency bands, respectively. Meanwhile, a negligible mutual coupling effect in middle band is achieved by using a collinear-placed transverse meander-line pair in the MIMO antenna. The antenna prototype measurement results show good impedance matching with low mutual coupling effect. The calculated envelope correlation coefficient verifies the suitability of the proposed antenna for mobile wireless access applications.