HIGH ISOLATION FOUR-PORT WRENCH SHAPED COMPACT UWB MIMO ANTENNA FOR 3.1-10.6 GHZ BAND

This present article reports a high isolation four-port Wrench shaped compact UWB MIMO antenna with a novel decoupling network in the ground plane, and its step-by-step evolution is presented for 3.1-10.6 GHz. The proposed four-port MIMO antenna is fabricated on an FR4 substrate of size 44 * 44[mm.sup.2] (0.342[[lambda].sub.0] * 0.342[[lambda].sub.0]), where [[lambda].sub.0] is a free space wavelength at 2.33 GHz, with 7mm edge-to-edge spacing between the radiating elements. It consists of four orthogonal symmetrically placed identical radiating elements each of which has a Wrench-shaped circular patch with a rectangular slot cut in the partial ground. The performance characteristics of this MIMO antenna are reflection coefficients [S.sub.11] [less than or equal to] -10 dB in the range from 2.33 GHz to 11.7 GHz, mutual coupling coefficients [S.sub.21] [less than or equal to] -28.24 dB, and [S.sub.31] [less than or equal to] -22.35 dB. The maximum peak gain is 5.15 dBi at 9.2 GHz, and minimum is 1.27 dBi at 3.1 GHz. The maximum efficiency is 98% at 4.66 GHz, and the minimum is 93% at 6 GHz. The diversity parameters of proposed four-port MIMO antenna are reported as ECC [less than or equal to] 0.2, DG [less than or equal to] 10, TARC [less than or equal to] -10 dB, the ratio of MEG between any two elements is near unity, and CCL < 0.38 bits/s/Hz in the band of interest. The design is fabricated and measured. The measured and simulated results are in good agreement and are within the permissible limits.