A Multilayer Unit-cell for Perforated Dielectric Transmitarray Antennas

In this paper, a new unit-cell is introduced with the aim of improving the efficiency and bandwidth of dielectric perforated transmitarray antennas. The behavior of the proposed unit-cell is compared with that of a conventional one, consisting of a single dielectric layer with a central square hole. In the structure here proposed, two additional tapered layers have been added, acting as matching circuits. Two transmitarray antennas of 40x40 elements, each using one of the two unit-cells, have been designed and numerically characterized. The results show significant performance improvements when the new unit-cell is used: the 1-dB Gain bandwidth increases from 13.4% to 27.6% and the aperture efficiency from 33.4% to 44%.