An antenna comprising a ground element, a first conductive element, a first transmission element, a second transmission element and a third transmission element. The first conductive element is connected to the ground element. The first transmission element is connected to the first conductive element extending in a first direction. The second transmission element is connected to the first conductive element. The third transmission element is connected to the first conductive element extending in a second direction opposite to the first direction, wherein the third transmission element nears the second transmission element, and maintains a distance from the second transmission element.