3D-Printed Wideband Dual-Polarized Hollow-Waveguide Antenna Array with Dual-Mode Back Cavity

This paper presents a wideband dual-polarized hollow waveguide antenna array fabricated using stereolithography (SLA) 3D printing and copper plating. A dual-mode back cavity, operating in TE210/TE120 and TE410/TE140 modes, is proposed to improve impedance bandwidth while maintaining stable radiation patterns. A diamond-shaped radiation slot is introduced to enhance cross-polarization isolation and mitigate high-frequency gain degradation. The antenna employs an all-hollow waveguide feeding network, facilitating ease of fabrication and metallization while ensuring low transmission loss. The measured results demonstrate a fractional bandwidth (FBW) of 30.2% (10.7–14.5 GHz), aperture efficiency exceeding 72%, and high polarization isolation (>50 dB).