Active frequency selective surfaces for beam switching applications

In this paper, a beam switching antenna with a novel active frequency selective surface (AFSS) is proposed at 5.2 GHz. The antenna is composed of an omnidirectional patch antenna and AFSS. The AFSS is made up of 6 columns, each with 2 unit cells, which are placed vertically around a patch antenna to form a hexagonal wall. To steer beam of the antenna, high frequency pin diodes are precisely inserted into the AFSS to reconfigure electromagnetic (EM) response of surfaces. The reflection and transmission characteristics of the proposed AFSS unit cell are investigated. The simulation results show that the transmission and reflection bands of AFSS unit cell can be changed by setting diodes on and off. This new AFSS can be used to implement a sweeping radiation pattern at all azimuth angles. The antenna can sweep the entire azimuth plane in six steps and effectively operate over a bandwidth of more than 500 MHz.