Patent ID: 7598921
Filing Date: 2009-10-06
Classification: H01Q

Abstract:
1. A folded antenna comprising: a ground plate; and an antenna element having a plurality of turning parts and a plurality of segments formed between the turning parts, the segments being formed by being turned back in a zigzag manner in parallel to one face of the ground plate at the turning parts, the antenna element extending perpendicularly to the one face of the ground plate, with one end connected to a feeding part and the other end open, wherein a length of one segment or a length of a set of segments, which is a pair of arbitrary two adjacent segments having the same length, is shorter on a side of the one face of the ground plate and increases gradually as the segment or the set of segments is away from the one face of the ground plate, and wherein the antenna element is formed such that the folded antenna resonates at two or more frequency bands and has a fractional bandwidth of 4% or more of the resonance frequency in a first frequency band and a fractional bandwidth of 15% or more of the resonance frequency in a second frequency band, by adjusting lengths of the segments or sets of segments having the same length, and intervals between adjacent segments, and a face opposed to the antenna element is free of any ground conductor.