360° Single/Dual-Beam Steering of an EBG Encircled Monopole Antenna by Controlling Ground Surface Currents

A monopole antenna encircled by an EBG ring is proposed for 360° beam steering with single-and dual-beam modes by controlling the currents on a ground. The monopole is located at the center of the square ground. The EBG ring is formed with 15 identical mushroom-like unit cells. The radiation beams are formed, and their directions are changed as the direction of the traveling surface current on the ground plane is controlled by combining the on/off states of the EBG unit cells. Simulated and measured results show the proposed antenna operating at 2.45-GHz band achieves single-beam scanning with 24° resolution and dual opposite beam scanning.