High-Gain $D$ -Band Transmitarrays in Standard PCB Technology for Beyond-5G Communications

We present novel three-layer D-band linearly polarized transmitarrays entirely fabricated using standard printed circuit board (PCB) processes. Three flat lenses comprising 1600 elements are designed to generate broadside and scanned beams. All lenses are synthesized using eight unit cells (3 bit phase quantization). The combination of cells comprising probe-fed and aperture-coupled patches is proposed to overcome the design challenges due to technological constraints and achieve a wideband operation. The minimum design feature is 80 μm. The tradeoffs in the design of the feed illumination are analyzed using ad hoc numerical tools. A 10 dBi horn is eventually selected as source. The focal-to-diameter (F/D) ratio is 0.75 for all lenses. The broadside array attains a peak gain of 33.0 dBi and a -1 dB relative gain bandwidth of 11.7%, i.e., wider than that of state-of-the-art designs, in the 100-300 GHz band, which use more complex technologies and larger focal distances. The performance of the proposed antenna technology demonstrates its potential for low-cost high-capacity wireless backhauls beyond 100 GHz.