Double-Layer 45° Linearly Polarized Wideband and Highly Efficient Transmitarray Antenna

Abstract

This letter presents a double-layer 45° linearly polarized (LP) wideband and highly efficient transmitarray antenna (TA). The proposed element is composed of two multi-resonant dipoles and four metal vias. The dipoles are placed on the diagonal of the unit cell and printed on both sides of the dielectric substrate. The metal vias which penetrate the substrate and connect the upper and lower dipoles are used to improve the transmission efficiency and obtain the large phase shift range of the proposed element. The proposed element realizes a full 360° phase shift range with a smooth slope in the band, and the magnitude loss is less than 1.5 dB at 20 GHz. The proposed TA is designed, manufactured, and measured. The measurement and simulation results are consistent. Measurement results indicate that the proposed TA has a maximum gain of 26.9 dBi at 20 GHz and an aperture efficiency of 53.5% with a 1 dB gain bandwidth of 12% (18.8–21.2 GHz). The proposed double-layer 45° LP TA shows enhanced bandwidth and simple design. Using a double-layer structure opens possibilities for TA design.