Research On The Multi-Beam Spherical Lens Antennas

Multi-beam antennas which can form multi-beams has important applications in millimeter frequency. It's good performance in multi-beam communication system is widely accepted by the research.Luneberg lens are commonly fabricate for a number of constant dielectric concentric shell to approximate the continuous dielectric distribution of luneberg lens formula.Firstly, this paper introduces the classification of the multi-beam spherical lens antennas, and gives the analysis of luneberg lens antennas and the spherical lens antennas, projecting the equation of the aperture and the far radiate field of the antenna.Secondly, this paper research on the performance of constant dielectric spherical lens antennas, discuss these parameters'influence on the performance of antennas which include the radius of the lens, the ratio of the distance between lens and feed waveguide and the radius of the lens, the dielectric of the lens and the aperture of the feed waveguide. It is deduced that the value of d/R is the most important fact.Then, this paper got the optimal luneberg lens using improved methods such as the equal thickness of layer and simplification and optimization methods base on GA. On 28GH and 35 GHz, the beam width of the main lobe is nearly 14 degree, the sidelobe level is low to -20dB,and the gain is up to 22dB. We know that the offset in narrow don't influence the performance of the luneberg lens antennas.Finally, this paper focus on the multi-beam luneberg lens antennas. We simulated a twelve square waveguide feed luneberg lens antennas, cover nearly 180 degree area, and we can equivalent the multi-beam luneberg can cover nearly half spherical region and switch the beam freely.