Minimizing Mutual Coupling in MIMO Antenna

Abstract

A MIMO antennas have gained a lot of importance in present wireless newlinecommunication systems due to its numerous benefits such as low multipath fading, newlineincreased capacity, high data rate and low co-channel interference. It employs more newlinethan one antenna element to transmit and receive the signals effectively. A MIMO newlineantenna deals with diversity schemes such as space diversity, polarization diversity newlineand pattern diversity to overcome the multipath fading. The main hurdle in designing newlinea MIMO antenna is to place the multiple antennas in a limited space to have a newlinecompact size and at the same time, to have high isolation between the elements. The newlinemultiple antenna elements when closely placed lead to high mutual coupling which newlinedegrades the radiation pattern, total efficiency and affects the overall performance of newlineMIMO system. Hence reducing mutual coupling is a major issue in designing a newlinecompact MIMO antenna structure. Therefore, different isolation techniques are used newlineto mitigate the mutual coupling. Various mutual coupling reduction techniques such newlineas EBG Structure, Defected Ground Structure, parasitic elements, etc. have been newlineemployed for MIMO antennas to lower the mutual coupling between MIMO antenna newlineelements. newlineThe research work deals with the study and implementation of isolation techniques newlinesuch as slits, dumbbell shape DGS and parasitic element in closely placed H shaped newlineMIMO antennas for WLAN applications. Further, compact wideband MIMO antennas newlinewith improved isolation is designed to covers applications such as 2G, 3G, WLAN, newlineWi-Fi, Bluetooth and UWB. Semicircular and trapezoidal monopole antenna are newlinemodified by adding rectangular steps, corrugating the edges, etching annular slot in newlinethe monopole antenna to improve the impedance matching over the wideband. To newlinereduce the mutual coupling over wideband, isolation structures such as modified SRR newlinelike structures, trapezoidal stub, and meshed metal strip are integrated in the ground newlineplane.