Multibeam Radiation Patterns for Various Lens Antenna Type With Positive and Negative Refractive Index

Negative refractive index (NRI) lens antennas offer the advantage of producing thinner lens profiles compared to conventional lenses. This study investigates positive and negative refractive index values for hyperbolic-planar, plano-convex, and spherical-convex lens antennas. These NRI lenses are expected to exhibit superior multibeam characteristics. The best feed positions are determined through focal region ray tracing to optimise performance. For refractive index values √2.17 (positive) and -√2.17 (negative), the focal regions of each lens shape are analysed, identifying the optimal feed position. Multibeam radiation patterns are generated using an electromagnetic simulator for positive and negative index lenses. The results indicate that all NRI lenses, which are thinner than their conventional counterparts, can have wide-angle beam scanning with enhanced multibeam performance.