Focal Array Fed Dielectric Lenses: An Attractive Solution for Beam Reconfiguration at Millimeter Waves

We investigate the radiation capabilities of focal array fed dielectric lens antennas using the FDTD method. Several relevant configurations sharing the same lens architecture (namely an extended hemispherical lens coated with a quarter wavelength matching layer), but illuminated by different sub-array topologies, are compared. In particular, we study the impact of the feeding amplitude coefficients, sub-array size and location upon the radiation patterns and beam scanning performance of the lens. Our numerical results demonstrate that such lens configurations are very attractive and flexible for beam synthesis at millimeter waves (beam shaping, beam scanning and beam reconfiguration). These conclusions are confirmed successfully by several experimental results in Ka-band obtained with a
$8 \times \lambda_{0}$
lens in Rexolite illuminated by linear printed antenna arrays of variable size.