A Wide Angle Scanning Spherical Luneburg Lens Antenna Employing Metamaterial

A novel design method for employing metamaterial to construct lightweight and high-efficiency spherical Luneburg lens (LL) antennas with a broad scanning range is presented. Based on the method, a spherical LL antenna with a diameter of 4.7λ at 3.5 GHz has been fabricated and tested with dual-linearly polarized square waveguide feeds. The prototype lens antenna performs well with full scan range in the azimuth plane and 60° field of view in the elevation plane across the band between 3.3 and 3.8 GHz. The peak gain is 22.8 dBi with less than 0.5 dB scanning loss, and the cross-polarization level is less than 25 dB for the vertical, horizontal, and slant incident polarization. Simulated and measured results agree well.