This paper discusses some of the open research topics that are important for the implementation of 5G mobile communication. Shortage of bandwidth has caused demand to change the architecture to support mobile communication which is currently used for 4G implementation. This architectural change includes the use of millimeter wave, MIMO and dense architecture. Use of millimeter wave is encouraged because it has been underutilized and offers more bandwidth but the drawback is the propagation of millimeter wave is limited due to its less penetration power. So use of Hybrid antenna can be used to provide spherical coverage. Hybrid antenna combines Antenna in package and Antenna on display to steer the antenna main lobe in the end-fire and broadside direction. Use of repeater which enables to regenerate lost energy of millimeter wave after fixed distance. Use of patch antenna for transmission of mmwave.