Review on Isolation Techniques in MIMO Antenna Systems

Objectives: Presently, wireless applications are quickly moving towards multiple input multiple output configuration, thereby the quest for integration of many antennas in the user’s equipment enhanced. A MIMO Antenna is used as a reason of enhancing the capacity of the channel without the need of additional power or frequency band. It requires many antennas set up in the transmitter with less coupling between them. Methods/Statistical Analysis: Hence, for an effective MIMO antenna system mutual coupling between the antennas should be low. Various MIMO antenna designs have been reported by antenna researchers for wireless application. The main design challenge in MIMO antennas is to attain high isolation amid the antenna elements. This paper reviews various isolation techniques proposed in the recent years. A detailed analysis on the design issues such as antenna miniaturization, integration issues, antenna coupling and isolation enhancement techniques are presented. Findings: among the isolation methods discussed better isolation is achieved using meta materials, decoupling networks and defected ground structures. Application: MIMO antenna systems find application in portable devices, automotive applications, handheld devices, personal digital assistant etc.Keywords: Decoupling Network, Defected Ground Structures, Isolation, MIMO Antenna, Metamaterials, Neutralization Line, Parasitic Elements, Return Loss