An antenna includes a conductor portion, a grounding portion and a radiator portion. The grounding portion includes a main section, first and second wings and a line section. The first and second wings extend respectively from opposite ends of the main section toward the conductor portion. The line section includes a base segment extending from the main section between the first and second wings toward the conductor portion, and an extension segment extending from the base segment toward the first wing. The radiator portion includes a feeding point adjacent to the main section, a base line extending from the feeding point toward the conductor portion and an extension section extending from the base line toward the second wing.