A wideband antenna includes a ground element comprising an upper first side, a first metal sheet a short arm connecting to the first side of the grounding element and a long arm separated from the first side, a second metal sheet electrically connecting to the first metal sheet, a third metal sheet perpendicular to the second metal sheet, and a slot between the first side of the ground element and the long arm of the first metal sheet; wherein said slot, said second metal sheet and said third metal sheet work together to form an ultra wide resonant frequency.