Wideband beam-steerable configuration of metasurface loaded slot antenna

In this article, a wideband two dimensional (2D) beam-steerable antenna structure is presented. The proposed structure is based on a radially gradient hybrid metasurface (RGHMS) illuminated through a slot antenna. The half aperture of the RGHMS comprises of a gradient phase profile topology, while its other half aperture consists of a constant phase profile configuration. The slot antenna possessing the bidirectional radiation pattern is printed on a relatively thin substrate, which operates over a wide bandwidth of 1420MHz (15.10%). The placement of RGHMS tilts the main beam of slot antenna by 15 degrees away from normal direction. Further, in-plane movement of MS provides beam steering in both elevation and azimuth planes, with a conical region of an apex angle of 30 degrees. Apart from the beam steering capability, the placement of RGHMS in front of slot antenna also enhances the overall bandwidth and gain by 360MHz and 5dB, respectively. Thus, a wide band beam steering configuration with the impedance bandwidth of 1780MHz (18.85%) is obtained. In order to investigate the frequency dependent beam tilting capability of the RGHMS in the elevation plane, a detailed analysis is carried out using the principle of refraction.