A Broadband Double Layer Transmitarray Using Polarization Rotating Elements

In this paper, a transmitarray adopting double-layered polarization rotating elements is proposed. By adjusting the dimension of the bowknot-shaped structure as well as mirroring the element's bottom layer, a phase shift of 360° with a high transmissive magnitude is obtained. Based on the proposed unit-cell, a double-layered circular transmitarray is designed. The simulation results indicate that 1-dB gain bandwidth of the transmitarray antenna is 19.6% and 3-dB gain bandwidth is 33.6%. In addition, the gain at 10 GHz is 26.4 dBi and the aperture efficiency is 51.6%.