Ridge Gap Waveguide Implementation with a 3D Glide Symmetric Holey Metasurface for Slotted Antenna Array Feeding

This work focuses on integrating Electromagnetic Band Gap (EBG) multi-layer glide-symmetry metasurface in a Ridge Gap Waveguide (RGW) feeding network. The presented RGW structure consists of four stacked metal layers. A formed path is created between the bottom and the top layer while each layer integrates a periodic pattern of holes. The integrated holes are arranged to configure a glide-symmetry metasurface. This metasurface is used to form boundary conditions for RGW feeding, effectively dealing with energy leakage. Also, EBG conditions allow the assembly of distinct layers without any required galvanic connection, avoiding delicate manufacturing welding processes. In addition, the hole metasurface utilization takes advantage of larger periodicity in comparison with metal pins, providing relatively higher manufacturing robustness and leading to higher tolerances and improved feasibility. To highlight potential applications, an eight-slot array antenna is presented. It is fed by the RGW with a 3D glide symmetric holey configuration. The slot array antenna covers an impedance bandwidth of 7.1%, from 37.64 GHz to 40.34 GHz, and provides a gain of over 14.5 dB.