A Novel Dual-Band Beam-Switching Antenna Based on Active Frequency Selective Surfaces

摘要

A novel design of a dual-band beam-switching antenna based on active frequency selective surfaces (FSSs) is presented. The antenna is composed of two layers of active cylindrical FSS and fed by a dual-band dipole at the center. The FSS layers are divided into on and off state sectors in both inner and outer layers. Each sector consists of columns of metallic strips with on or off state diodes. To achieve a dual-band matching, the inner FSS layer is transmissive at lower band in both on and off state. Also, it is reflective in the on state and transmissive in the off state at higher frequency band. The outer layer is a reflective surface in on state and transmissive in off state in both frequency bands. In each state of operation, the on state sectors operate as a reconfigurable reflector at both frequency bands and convert the omnidirectional radiation pattern of the dual-band dipole to a directive one. By switching the states of diodes, the antenna can scan the entire azimuth plane. The fullwave simulation results show the antenna operates at 0.75 GHz-1 GHz and 1.7 GHz-1.9 GHz simultaneously, with maximum gain of 6.4 dBi and 10 dBi respectively, and can be used in the base stations of wireless communication systems.