This communication introduces a wideband hollow-waveguide (HW)-based dual-polarized antenna (DPA) with reduced metal layers. A new normal-size 4-to-4 cavity is backed with the 2 2 radiating slots in subarray to directly generate dual-polarized radiation. It not only significantly widens the bandwidth, but also enables the period of the radiating slots to be less than one free-space wavelength across the operating frequency band. The E-plane horizontal and vertical power dividers are nested between each other, working as the feeding networks in the subarray to support H- and V-pol, respectively. This topology can not only constrain the four output ports within the footprint of the normal-size backed cavity (to meet the period requirement of the radiating slots), but also help reduce the feeding network to two metal layers for easy fabrication. By interconnecting multiple subarrays through corresponding E- and H-plane T-junctions, a large-scale DPA can be constructed. For validation, a 4 4 slot DPA prototype operating at Ku-band is demonstrated. The measured results show that the bandwidth with grating lobes suppression is up to 35.2% (10.5–15 GHz). In addition, the isolation between the two input ports is better than 50 dB and the antenna efficiency is higher than 90%.