Performance Analysis of Planar Luneburg Lens and Full Dielectric Lens

A planar Luneburg lens antenna (PLLA) and a planar full dielectric lens antenna (FDLA) are designed with the same radius in the same frequency band for comparison. To convert the incident spherical wave into an outgoing planar wave, the PLLA requires concentric-ring layered distributed permittivity, while the FDLA is comprised of a full dielectric disc. Both the two lenses have been excited with the same feed antenna, and their performance is investigated as follows: the impedance bandwidth
$(\vert \mathcal{S}-{11}\vert \leq-10\mathbf{dB})$
of PLLA is 25.2-29.4 GHz, and its peak gain reaches 16.4 dBi; the impedance bandwidth
$(\vert \mathcal{S}_{11}\vert \leq-10\mathbf{dB})$
of FDLA is 25-30.3 GHz, and the peak gain reaches 16.5 dBi. It shows that the FDLA can achieve a similar performance as that of PLLA, and it has a much simpler structure than the latter, suitable for low-cost applications.