“…For example, many DRAs employ very special geometric shapes, such as flipped staired DRAs, H-shaped DRAs, T-shaped DRAs [4][5][6], or employ different dielectric constants, such as multilayer ring DRAs or perforated DRAs [7][8][9]. Other structures may employ even more exotic structures, such as hook shaped DRAs [10], Y-shaped DRAs [11], pixelated DRAs [12], multiple circular sector DRAs [13], or have notches [14] and hollow regions in their DRA structures [15]. These structures, even though they may possess remarkable features, such as wide bandwidths, high gains, or multi-band operation, may not be easily manufactured using common methods and materials.…”