A 4 element compact Ultra-Wideband MIMO antenna array

In this paper, a compact planar Ultra-Wideband (UWB) antenna array with 4 monopole radiators is presented. To enhance the isolation, polarization of nearly placed elements is exploited. The proposed MIMO antenna array is electrically small 50 × 39.8 mm², printed on a low loss 1.524 mm thick Rogers TMM4 laminate with a dielectric constant of 4.5 and a loss tangent of 0.002. Simulation in HFSS and printed prototype results satisfy the return loss requirement of better than 10 dB and isolation better than 17 dB on the entire 2.5 to 12 GHz bandwidth. The calculated envelope correlation value of less than 0.03 and the compactness of the proposed antenna array makes it suitable for small portable handheld devices.