A Broadband Low-Profile Folded Transmitarray Antenna Based on Metasurface

A broadband low-profile folded transmitarray antenna is proposed based on metasurface(MS). The antenna consists of a transmitarray and a reflective surface (RS). In the transmitarray element design, the I-shaped resonator is placed in the middle of two substrate layers, while the upper and lower metallic layers are two orthogonal polarization gratings. The I-shaped resonator is also used in the RS element. By adjusting the size of the I-shaped resonator on both transmitarray element and RS element, the transmitting phase and the reflecting phase can be designed. Based on the above theory, the ratio of the height of the profile to the aperture of the array is reduced to 0.16 and the profile is reduced to 1/5 of the focal length. The simulated results show that the proposed antenna can achieve a peak gain of 24.8 dBi, a peak aperture efficiency of 54%, a 1-dB gain bandwidth of 18.4% and a 3-dB gain bandwidth of 35.4%.