Design of a Wideband Transmitarray (TA) Antenna With Subwavelength Thin Metasurface

This report presents the design of a high-performance wideband transmitarray (TA) antenna featuring a low-profile, 2-bit subwavelength metasurface (MS) array. The antenna employs an optimized Potter horn (PH) as the source feed and an innovative metasurface structure, enabling seamless 360∘ phase coverage with 90∘ linear phase variations. The metasurface is constructed using three metallic layers on RT/Duroid 5880 substrates, with polarization-selective top and bottom surfaces and a polarization-rotating middle layer incorporating a 45∘ rotated dipole resonator and a square ring corner cut. A wideband response is achieved using the generalized scattering matrix (GSM) method, while the mixed-integer sequential optimization ensures optimal tapering of the PH feed. The circular aperture design, comprising 729 elements, is guided by the generalized phase distribution method. The antenna exhibits exceptional performance with a peak gain of 27.2 dBi, aperture efficiency (AE) of 58.5% at 32 GHz, and sidelobe levels suppressed below -24 dB across the operational band. Notably, the 1-dB and 3-dB gain bandwidth (GBWs) are 12.69 GHz (39.68%) and 15.84 GHz (49.2%), respectively. Fabrication and experimental validation confirm reasonably good agreement with simulation results, emphasizing the TA antenna’s robustness and reliability. Its advanced design and superior performance make it ideal for applications in Ka-band radio astronomy and space communication.