An antenna includes a grounding portion extending in a longitudinal direction, a main body and an isolating portion extending from the grounding portion, a metal foil assembled on the grounding portion and a coaxial cable connecting the main body. The grounding portion includes a first section and a second section connecting with each other. The main body extends from the first section while the isolating portion extends from the second section. The isolating portion locates beside the main body in the longitudinal direction and defines a gap therebetween.