Reduction of Mutual Coupling in Planar Multiple Antenna by Using 1-D EBG and SRR Structures

One-dimensional electromagnetic bandgap (1-D EBG) and split ring resonator (SRR) structures were inserted between two closely located monopole antennas to suppress mutual coupling. The 1-D EBG and SRR structures in these planar multiple antennas function as a reflector and wave trap, respectively. With the effect of these two structures, the mutual coupling between the two antennas is reduced by more than 42 dB and the back lobes are reduced by 6 dB. Thereby, the radiation efficiency of the antenna is also improved. The two fabricated antennas with 0.19 lambda(0) spacing exhibit mutual coupling (S-21, S-12) of less than -30 dB from 2.43 to 2.54 GHz. A minimum correlation coefficient of 0.002 and maximum radiation efficiency of 82% are also demonstrated.