Broadband Folded Transmitarray Antenna Based on an Ultrathin Transmission Polarizer

In this paper, low-profile broadband planar folded transmitarray antennas (FTAs) are proposed and studied based on a novel Fabry-Perot polarizer. A novel element is proposed to carry out high-efficiency transmission, the phase compensation and the 90 degrees polarization rotation at the same time. The element consists of two identical dielectric slabs, sandwiched by three metal layers, and has a thickness of only about 0.1 lambda. To verify this element, a transmitarray antenna is first designed and its highly efficient radiation performance is demonstrated by both simulations and the experiments. Low-profile FTAs are then designed and studied. The results show that the advantages of broad bandwidth, high gain, lower profile, planar geometry, and ease of integration can be achieved. The experiments of the FTA antenna demonstrate a 3 dB gain bandwidths of 18% and a peak gain of 25.2 dBi.