Research on the development of a multi-beam negative refractive index lens antenna for a base station in mobile communications in the 28 GHz band

1. Propose a solution to calculate and determine the negative refractive index lens antenna structure according to Straight line conditions operating in the 28 GHz band. Using a negative refractive index lens helps reduce the lens size compared to using a positive refractive index lens: The positive refractive index lens thickness with Abbe sin condition (28.66 mm) and hyperbolic shape (24.51 mm) is reduced to 6.1 mm at the edge and to 1.0 mm at the center when replaced with negative refractive index lenses. Calculating and determining the structure of the negative refractive index lens antenna with Straight line condition help the lens antenna to have the maximum gain of 27.48 dBi, low sidelobe level at -25.10 dB, and better radiation characteristics than those of negative refractive index lens antennas with a conventional structure. The proposed solution has been verified on MATLAB and Ansys HFSS software.
2. Propose a solution to design a multi-beam negative refractive index lens antenna based on the ray tracing method in order to be applied to base stations in mobile communications in the 28 GHz band. By using the ray tracing method, the author has calculated and determined the areas of focus and their trajectories for negative refractive index lens antennas. Besides, propose a solution to design a negative refractive index lens antenna with the Straight-line condition creating multi-beam with wide-angle beam scanning by setting the feeds on the determined areas of focus and trajectories. The results show that the lens antenna with the proposed structure is capable of generating many beams with wide-angle beam scanning in the range ±48.84° while the peak gain is still higher than 23.72 dBi and the attenuation of the radiation of the lens antenna with the proposed structure is less than that of other structures when the feed is set up off-axis. The proposed solution has been verified on MATLAB and Ansys HFSS electromagnetic software.