A Metasurface Based High-Gain Dual-polarized Flat Luneburg Lens Antenna

Abstract

A dual-polarized flat Luneburg lens antenna (FLLA) is designed using reflection cancellation method to improve its gain and bandwidth. First, the performance of conventional Luneburg lens (LL) and flat LL is compared to show that the increased permittivity in the flat LL degenerates the gain due to the severe reflection. During the implementation of flat LL, the reflection cancellation method is applied by adjusting the airgap between layers, so that a high-gain performance is achieved over a wide bandwidth. The designed FLLA is exemplified over 25-35 GHz, and fed by a dual-polarized patch antenna. The measurements show that the impedance bandwidth (|S 11 | ≤ -10 dB) is 27.6-32.7 GHz, and its peak gain reaches 18.8 dBi.