The antenna includes a metallic enclosure having a height dimension. At least one slotted opening is formed along the metallic enclosure. Each slotted opening has a slotted opening length and a slotted opening width. The slotted opening length is at least twice as long as the slotted opening width is wide. The slotted opening width is less than one wavelength wide and the slotted opening width is within a half wavelength of the height dimension. At least one feed is provided at least partially within the enclosure.