Patent ID: 7330154

Claim:
An antenna device built into a casing, the antenna device comprising: a first antenna element disposed in the casing; a second antenna element disposed in the casing, the second antenna element being formed on the first antenna element; a grounding conductor disposed in the casing; and a switch unit that is disposed between the second antenna element and the grounding conductor and opens and closes the second antenna element and the grounding conductor, the switch unit switching connection of the second antenna element and the grounding conductor, wherein an antenna comprising the first antenna element or the second antenna element is configured as a result of the switch unit being switched to an open state, and an antenna comprising the first antenna element and the second antenna element is configured as a result of the switch unit being switched to a closed state wherein the switch unit is opened and closed depending on distance between the first antenna element and the grounding conductor, and wherein the switch unit is closed to configure an antenna comprising the first antenna element, the second antenna element and the grounding conductor in case where the first antenna element and the grounding conductor are close, and the switch unit is opened to configure an antenna comprising the first antenna element or the second antenna element in case where the first antenna element and the grounding conductor are not close.