Single-Layer Cavity-Backed Slot Array Fed by Groove Gap Waveguide

An effective feeding procedure for slotted waveguide arrays in the context of so-called groove gap waveguides (GGWs) is presented. Slots are fed through a corporate feed network with E-plane splitters and backed by coaxial cavities, which are more compact than conventional cavities. The coaxial cavity is integrated within the same bed of nails used to host the groove in the gap waveguide. The cavity resonance is generated by merely lowering the height of the desired nail with respect to the surrounding ones. Therefore, no increase in complexity is introduced. The feeding network is built in the same layer as the cavities and the slots, considerably reducing array volume compared to multilayer topologies. A $4 \times 4$ slot array has been designed using this concept. The goal of this letter is to demonstrate the viability of groove gap waveguides and coaxial cavities for the design and fabrication of high-frequency single-layer slot-array antennas. Simulation results as well as measurements are shown.