A antenna for transmitting radio signals of a lower frequency and a higher frequency includes a driven element comprising two first radiating units for a lower frequency band and two radiating units for a higher frequency band, and a reflector element comprising a first reflecting unit for the lower frequency band and a second reflecting unit for the higher frequency band. The second radiating units are disposed at a side of the first radiating units and respectively coupled to a corresponding first radiating unit. The first reflecting unit is disposed at the other side of the first radiating units, and the second reflecting unit is disposed between the first radiating units and the first reflecting unit.