“…Antenna array concepts established for 5G operation in microwave-frequency bands use several types of elements, such as a planar dipole [10,11], patch [12,13] and Vivaldi [14,15] structures, substrate integrated waveguide (SIW) [16][17][18], and slotted [19] and horn (including various ridges) [20][21][22][23] waveguides. The elements based on the planar dipole, patch and Vivaldi structures, and SIW are easy to manufacture and integrate with other planar microwave circuits; however, they may exhibit higher losses since their metallic structures are supported by a dielectric substrate.…”