Multiport MIMO antennas with mutual coupling reduction techniques for modern wireless transreceive operations: A review

The present technology fulfills the requirement of high data rate and high channel capacity using multiple input multiple output (MIMO) technology. The MIMO capacity of the system is increased linearly but due to the multiple antennas placed near to each other, problem of mutual coupling exists, which degrades the maximum achievable performance of the system. The problems of multipath propagation can be solved using MIMO system. The isolation improvement methods decrease the mutual coupling among antenna elements, and improve the gain and efficiency of the system. In this paper, decoupling network isolation approach, parasitic element approach, defected ground structure, Neutralization line, isolation improvement based on metamaterials, isolation improvement using PIN diode, varactor diode, and feeding structure have been incorporated, and their merits and demerits have been discussed. The effect of different permittivity material on antenna parameters has also included.