Caustics and Beam Steering Calculations of Negative Refractive Index Lens Antenna by the Ray Tracing Method

A negative refractive index lens antenna has a high direction, a capacity to produce multiple beams and beam steering with a thin antenna size. These characteristics enable the lens antenna to be chosen as one of the effective antennas for the base station antenna in mobile communications, meeting the rapid growth in wireless connections. In this paper, the authors use a ray tracing method to calculate and determine the caustic points and their trajectories for a negative refractive index lens. These caustic points are the feed-setting positions from which the antenna can generate the beams at the desired angles. The authors also perform the simulations of negative refractive index lens antennas with feed horns set at caustics and reference feed points. The results show the accuracy and efficiency of the calculation of caustic points and the beam steering ability of the lens antennas with negative refractive indexes.