A Highly Efficient Spherical Luneburg Lens for Low Microwave Frequencies Realized With a Metal-Based Artificial Medium

This article describes a novel spherical lens antenna constructed of planar layers lightweight foam with equally spaced conducting inclusions varying sizes on an orthogonal grid. construction largely overcomes the problems weight and cost that have tended to make larger low-frequency Luneburg lenses impractical. A penalty for this type design is some anisotropy exists in lens's dielectric. effect examined using both ray-tracing techniques full-wave simulation, it found principal consequence focal length varies different directions. Methods mitigating are proposed. prototype intended cellular use band 3.3-3.8 GHz dual-linear slant polarized feeds was designed confirm findings. The measured results show peak gain 23 dBi, which less than 1 dB lower maximum possible directivity from cross-sectional area. Scanning loss 0.8 over whole sphere. simulated performances excellent agreement overall performance demonstrates should be very suitable high-gain multibeam antennas at microwave frequencies.