A dual-band antenna is disclosed including: a first antenna comprising: a first radiating portion including a plurality of separated radiating strips positioned on a first plane of a circuit board; a second radiating portion including a plurality of separated radiating strips positioned on a second plane of the circuit board; and a plurality of vias for coupling the plurality of radiating strips on the first plane with the plurality of radiating strips on the second plane to form a spiral radiating body; a second antenna having a radiating plane coupled with the first radiating portion or the second radiating portion; a shorting element coupled with the radiating plane and shared by the first and second antennas; and a feeding element coupled with the radiating plane and shared by the first and second antennas; wherein the width of part of the radiating plane gradually increases along a direction.