Coupling reduction of two element MIMO antenna using parasitic element for LTE band application

This paper presents a two triangular patch MIMO antenna using parasitic element for enhancing isolation which is aimed to function in the LTE band covering from 1.7 GHz to 3.6 GHz. The parasitic element is a planar interdigital line structure placed between the patches on top of the substrate. The antenna covered an impedance bandwidth of (1.5 to 3.58) GHz with return loss of -18.16 dB and -12 dB at 2.26 GHz and 3.25 GHz during simulation. A fractional bandwidth of 92% was achieved. An isolation of -20 dB and -20.5 dB was observed during simulation at 2.26 GHz and 3.25 GHz. With a very close by spacing of 0.074 lambda the proposed antenna exhibits a better performance compared to the previously reported designs in the literature by providing 53.3% less space. The antenna had good radiation characteristics in both E-plane and H-plane for all the operating frequencies. The simulated envelope correlation coefficient is below 0.002 and the total active reflection coefficient is below 0.40 throughout the band with a gain of 2.28 dB and 4.30 dB during simulation. The proposed antenna was fabricated and tested. The measured results are in good agreement with the simulation.