Mutual coupling reduction using variable length srr like structure in ultra wideband MIMO antennas

In this paper mutual coupling reduction in two element MIMO antenna structure using a SRR like structure with variable length is proposed. The structure consists of two modified elliptical shaped monopole antennas with the interelement spacing of 23 mm are fabricated using 0.787 mm thick RT Duroid substrate. S11 and S21 less than -10 dB and -18 dB respectively are obtained over 3.1-10.6 GHz. The proposed structure has a good diversity performance, nearly constant group delay and transfer function variation within 10 dB over UWB.