Agile Radiation-Pattern Antenna Based on Active Cylindrical Frequency Selective Surfaces

The design and implementation of an agile antenna at 2.45 GHz based on a grid of discontinuous strips incorporated with active elements on a cylindrical frequency selective surface (FSS) are presented. By benefiting from the feature introduced in the proposed surface, a reconfigurable stopband screen is created to emulate a cylindrical electromagnetic transparent/opaque surface. This surface is used to implement a sweeping-beam agile antenna covering all azimuth angles. The measured results confirm the concept of the proposed configuration. This antenna can effectively operate over a bandwidth of more than 200 MHz. Furthermore, the achieved back-lobe level for the directional radiation pattern is about -13 dB at the frequency of 2.55 GHz.