Enhancement of Tilted Beam in Elevation Plane for Planar End-Fire Antennas Using Artificial Dielectric Medium

This communication describes a simple and effective beamtilting technique for planar end-fire antennas using an artificial dielectric layer. The proposed approach is based on the phase differential resulting from a high refractive-index medium that is achieved using double G-shaped resonators (DGRs) in a 5 x 4 array. The array is oriented normal to the direction of the main beam emanating from the antenna. To demonstrate the principle, the technique is applied to a bow-tie antenna, which is designed at the WiMAX frequency band (3.4-3.6 GHz). The antenna performance was verified practically, and the measured results confirm that the direction of antenna's maximum beamcan be refracted by 35 degrees in the H-plane, which is larger than conventional techniques. In addition, a maximum gain enhancement of 5 dB is achieved when the beam is tilted. Reflection-coefficient of the proposed structure is maintained better than -10 dB across its operational band.