  In this paper, a compact wideband dual-polarized Luneburg lens antenna (LLA)
with reduced anisotropy and improved impedance matching is proposed in Ka band
with a wide 2D beamscanning capability. Based on transformation optics, the
spherical Luneburg lens is compressed into a cylindrical one, while the merits
of high gain, broad band, wide scanning, and free polarization are preserved. A
trigonometric function is employed to the material property of the flattened
Luneburg lens with reduced anisotropy, thus effectively alleviates the strong
reflection, the high sidelobes and back radiation with a free cost on the
antenna weight and volume. Furthermore, a light thin wideband 7-by-1
metasurface phased array is studied as the primary feed for the LLA. The
proposed metantenna, shorted for metamaterial-based antenna, has a high
potential for B5G, future wireless communication and radar sensing as an
onboard system.
