A Compact Low-Profile Folded Transmitarray Antenna

A compact low-profile folded transmitarray antenna (FTA) is designed. The antenna includes a top transmission surface (TS), a bottom reflection surface (RS), and a planar feed. The transmission element employs a couple of vertically oriented C-shaped slits etched on a single-layer substrate's opposite sides. The 360°phase span with high transmission amplitude is realized by adjusting the C-shaped slit length and mirroring the element bottom layer. The reflection element is composed of a metal patch printed on a dielectric substrate, which can realize polarization conversion. The profile of the proposed array is reduced to 1/3 of the focal length of the traditional transmitarray, and the profile-to-diameter ratio is 0.22. The simulation results demonstrate that the antenna 3 dB gain bandwidth is 13% and the peak aperture efficiency is 33%.