W-Band High-Efficiency Low-Profile Four-Folded Transmitarray Antenna Based on Dual-Phase Compensation Strategy

Abstract

A novel high-efficiency low-profile four-folded transmitarray antenna (FTA) is proposed. The FTA is composed of a dual-functional transmit-reflected array (TRA) and a polarized conversion surface (PCS) based on single-layer PCB. The work proposed a novel dual-functional transmit-reflected element and dual-phase compensation strategy. Firstly, dual-functional transmit-reflected element is composed of double pairs of U-shaped and cross-shaped patches to realize efficient transmission and reflection, with the losses under 2 dB. Thus, high-efficiency dual-functional transmit-reflected array can be achieved. Secondly, dual-phase compensation strategy for primary and secondary arrays is put forward to realize low profile folding configuration, which is capable of achieving a profile compression ratio of no more than 0.25. Different from conventional FTA designs, no polarized grids, metal vias or bonding layers are required. For demonstration, one FTA prototype working in W-band is designed, fabricated and measured. The total size of the FTA is about 60 × 60 × 15.75 mm³. The measured peak gain and aperture efficiencies are 28.68 dBi and 21.38% at 89 GHz with 3-dB gain bandwidth of 10%, which achieved the highest gain and aperture efficiency in current W-band research. Benefiting from high-efficiency, low-profile, single-layer fabrication, as well as easy integration, the proposed FTA is expected to be a competitive candidate for vehicle radar and LEO satellites communication systems in high frequency of millimeter wave band to terahertz band.