Radiation pattern reconfigurable antenna: The design challenges at GHz frequencies

This paper presents the design challenges that could be faced by radiation pattern reconfigurable antenna in the Gigahertz (GHz) frequencies. This is due to the close relationship between the antenna radiation mechanism to the insertion loss and isolation loss contributed by RF switch at ON and OFF state respectively. Apart from that, the size of the antenna at higher frequencies especially above 10 GHz will be intrinsically small, thus requiring the methods for the installation of the RF switches on the antenna to be critical. In this paper, the theory and existing works on radiation pattern reconfigurable antenna are reviewed. Useful insights will be proposed in this review for future consideration in designing and implementing radiation pattern reconfigurable antennas above 20 GHz with satisfactory performance.