Beam switching antenna based on active frequency selective surfaces

In this paper, a beam switching antenna based on a new active cylindrical frequency selective surface (ACFSS) is proposed at 2.45 GHz. The proposed active frequency selective surface (AFSS) unit cell consists of the two crosses and a high frequency pin diode. The pin diode is precisely inserted between two crosses. The reflection and transmission characteristics of the proposed AFSS unit-cell structure are investigated. Results show that by controlling states of pin diode, the transmission and reflection bands can be changed. This new ACFSS is used to implement a sweeping-beam flexible antenna covering all azimuth angles. The simulated results confirm the concept of the proposed configuration. This antenna can effectively operate over a bandwidth of more than 500 MHz. Moreover, the achieved back-lobe level for the directional radiation pattern is about -12.5 dB at the frequency of 2.45 GHz.