An antenna including a rectangular ground plane, a feed point disposed in a vicinity of a corner of the ground plane, an antenna element coupled to the feed point, and a parasitic element coupled to the ground plane. In this antenna, the shortest length from the feed point to a distant narrow side of the ground plane and a shortest length from the feed point to a tip of the parasitic element via the ground plane have substantially the same electrical length. Such a configuration can correspond to a small and thin size and reduce SAR easily.
1. An antenna comprising:
a rectangular ground plane;
a feed point disposed in a vicinity of a corner of the ground plane;
an antenna element coupled to the feed point; and
a parasitic element coupled to the ground plane,
wherein a shortest length from the feed point to a distant narrow side of the ground plane and a shortest length from the feed point to a tip of the parasitic element via the ground plane have substantially same electrical length.
2. The antenna of claim 1 , wherein an inductor is disposed between the ground plane and the parasitic element, or in a middle of the parasitic element, or at the tip of the parasitic element.
3. The antenna of claim 1 , wherein a switch is disposed between the ground plane and the parasitic element.
4. The antenna of claim 1 , further comprising a holding portion made of insulating resin,
wherein the holding portion holds the antenna element and the parasitic element.