This letter presents a V-band [(57 to 66) GHz] 45 degrees linearly polarized 8 x 8-slot array antenna fed by a wideband groove gap waveguide (GGW)-based 1-to-16 corporate-feed network with enhanced robustness while maintaining good machinability. By employing a 2 x 2 subarray with 45 degrees twists, low sidelobe levels are realized while cross-polarization is maintained low. Besides, by adopting smaller rectangular pins, and then properly designing the width of GGW and spacing of periodic pins, the number of pin rows, separating two parallel grooves, is ensured to be at least two, thereby further reducing mutual coupling between grooves. Moreover, by applying three novel wideband components providing different benefits to the corporate-feed network, a wideband feeding network is obtained. For demonstration, an 8 x 8-element prototype is fabricated and measured. The experimental results present good agreement with simulated performance, which verifies the design validity.