A distribution feed network is designed on the backside oflayer 3. The outputs of the diplexer are coupled to the nextlayer, i.e., the feed network, via a right-angle GGW to therectangular waveguide (RW) transition. The feed network isdesigned in ridge gap waveguide (RGW) in order to accom-modate the corporate feeding of the array antenna elementswithin a limited available space. We have used a 2×2 cavity-backed slot subarray as the radiating element of the designedarray antenna. The radiating part consists of 8 × 8 subarraysthe slots on topside of layer 3. (c) View of the bottom side of layer 3 containingthe corporate feednetwork. (d) Diplexer on the bottom side of layer 2