Single-Glass-Layer Optically Transparent Transmitarray With High Aperture Efficiency and Low Profile at 5G Millimeter-Wave Band

This communication presents a single-glass-layer optically transparent transmitarray (TTA) with high aperture efficiency at millimeter-wave (mmWave) 5G band. When designing a transmitarray (TA), the more metal and dielectric layers are used, the easier it is to increase the aperture efficiency. However, if the TTA is designed, the fewer metal and dielectric layers, the more advantageous it is in terms of optical transparency (OT). Therefore, only a single glass layer was chosen to design a TTA with high OT. The novel analysis technique was applied to obtain the theoretical transmission response of the single substrate unit cell (UC) and to obtain impedance information to quickly design UCs by combining circuit analysis. Then, the aperture efficiency was increased using two methods: 1) two types of double resonance UCs were combined and 2) oblique incidence on the UCs on the edge of TA aperture was considered. The designed TA was converted into the TTA, which satisfies the advanced OT guidelines proposed in this communication. The fabricated TTA has a focal length (F) to dimension (D) ratio of 1.2, exhibiting simulated and measured aperture efficiencies of 51.1% and 45.3%.