Research of reconfigurable switched beam-forming antenna for wireless communications system

Abstract

Recently, due to increase use of smart device as smart phone and tablet PC, requirements for high quality and high performance wireless communications systems have grown to provide reliable high data rate with terminal user. Also, channel environments of wireless communications system are various by environment density and data traffic, which are LOS, NLOS and moving environment and so on. Therefore, channel adaptive antenna is required for capacity performance in high performance mobile communications system, such as beam-forming antenna with various beam-pattern. In this paper, reconfigurable beam-forming antenna which is compensated for implementation disadvantage of conventional phased array antenna and performance disadvantage of conventional switched array antenna has been proposed. The proposed reconfigurable switched beam-forming antenna has $(2^N-1)$ beam-pattern with N-array by reconfigurable power distribution in antenna. The reconfigurable power distribution is generated by reconfigurable power divider, which is composed of switches and microwave passive circuits, and beam-patterns are determined by beam-forming matrix with fixed phase condition. Also, multi-input reconfigurable beam-forming antenna for multiplexing performance has been proposed by utilizing the proposed reconfigurable structure. Finally, to optimize the radiation performance for the proposed antenna, mutual coupling effect in switched array antenna is analyzed and compensation method has been presented. Eventually, the experimental results show the proposed reconfigurable switched beam-forming antenna can be extensively utilized in high performance and low cost RF system, such as repeater and terminal system in mobile communications system.