Generate of a Near-Field Flat-Top Shaping Beam for a Transmitarray Antenna

Abstract

In this paper, we propose a transmitarray (TA) antenna designed to generate a near-field flat-top beam. The transmitting surface measures $127.5 ~\text{mm} \times 127.5 ~\text{mm}$ in size and comprises a $17 \times 17$ supersubunits. The near-field focusing plane is set at $z=120 ~\text{mm}$, with a 3 dB focal spot size of 52 mm. To achieve the design of the near-field flat-top beam, this study introduces a deep learning (DL) algorithm for phase-only optimization. A TA antenna model was subsequently established in HFSS for simulation verification, and the results demonstrated excellent agreement with the algorithm's optimization outcomes. Finally, the TA antenna was fabricated and tested, yielding flat-top focal spots on the $z=120 ~\text{mm}$ focal plane. Additionally, flat-top focal spots were also observed on the $z=110 ~\text{mm}$ and $z=130 ~\text{mm}$ planes.