Groove Gap Waveguide Slot Array Based on Glide-Symmetric Holes

Gap waveguide technology enables a cost-effective and low-loss manufacturing of high frequency fully metallic components. With this technology, the microwave components can be made in two pieces that are assembled together afterwards. Between these two pieces, an undesired air gap due to surface roughness or manufacturing tolerances may cause energy leakage. To prevent this leakage, periodic structures that produce electromagnetic bandgaps (EBGs) are used. Here, we compare the performances of two holey EBG surfaces, which are a conventional holey periodic metasurface and a metasurface with glide symmetry. The glide-symmetric structure has a wider EBG and a similar leakage prevention with less number of hole rows. Using glide-symmetric holes, a $4 \times 4$ slot array antenna is designed. This slot array is excited with the TE
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mode and has a rotationally symmetric radiation pattern.