W-Band Double-Layered Dual-Linearly Polarized Vialess Transmitarray Without Using Air Gap

A W-band double-layered dual-linearly polarized transmitarray (DLPTA) is proposed for the first time by utilizing hybrid vialess unit cells (UCs) of three kinds for maximizing the phase coverage. At W band, the main challenge in designing transmitarrays relies on finding proper UCs without using multilayered structure or coupling vias. To conquer the restriction, three complementary UCs, the square ring-slot UC, the crossed-slot UC, and the meandered-strip UC, are developed each responsible for a specific range of transmitting phase with stable frequency response. By integrating the UCs, a DLPTA at 79 GHz is reported, which shows a peak gain of 29 dBi, an aperture efficiency of 37%, and a broad 3 dB bandwidth of 14%. The design methodology is discussed along with a comparison table to manifest the uniqueness of the design.