Enhancement of tilted beam in elevation plane for planar end-fire antennas using artificial dielectric medium

This paper describes a simple and effective beam tilting 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 by using double G-shaped resonators (DGR) in a 5×4 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 the antenna’s maximum beam can be refracted by 35o 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