Double-Layer Wideband Transmitarray Antenna

This paper proposes a double-layer broadband transmitarray antenna (TA) unit based on multi-resonant structure. The TA unit consists of only two layers of metal patchs which printed on a dielectric substrate. Four symmetrical metal cylinders are used to connect the two layers of patches. The overall thickness of TA unit is
$0. 133\lambda_{0}(\lambda_{0}$
is the free space wavelength at 20GHz). By changing the size of the metal patch, flat phase curve and great transmission characteristics are achieved in K-band. It is also insensitive to the angle of incidence. In order to verify the broadband characteristics of the unit, the transmitarray antenna composed of 256 units was simulated. The simulation results show that the transmitarray antenna achieves a 1-dB gain bandwidth of 22.2% (19.21GHz-24.1GHz), a maximum gain of 24.2dBi, an aperture efficiency of about 43% at 20GHz, and a cross-polarization level better than -50dBi. The designed unit was symmetrical structure, so the transmitarray antenna can work in dual linear polarization or dual circular polarization. It has a good application prospect.