Patent ID: 6914573

Claim:
An antenna device having ultra wide bandwidth (UWB) characteristics, comprising: a ground element having a cutout section with an inner circumference, the inner circumference having a first shape; and a driven element with an outer circumference having a second shape, the driven element being smaller in size than the cutout section and being situated within the cutout section to define a clearance area between the driven element and the ground element, wherein the first shape is a first simple closed curve having no cusps, including a plurality of first concave portions and a plurality of first convex portions, wherein the second shape is a second simple closed curve having no cusps, including a plurality of second concave portions and a plurality of second convex portions, wherein the first and second shapes are formed such that any radial line from the center point of the driven element will intersect the first shape at a single first intersection point, and will intersect the second shape at a single second intersection point, a distance on the radial line between the first and second intersection points being defined as a clearance width between the driven element and the ground element for the radial line, and wherein the clearance area is tapered such that a clearance width between the driven element and the ground element is monotonically nondecreasing from a minimum clearance width to a maximum clearance width.