A mobile device includes a ground plane, a first antenna, a second antenna, a first metal element, and a second metal element. The first antenna has a first feeding point coupled to a first signal source. The second antenna has a second feeding point coupled to a second signal source. The first metal element has a connection end and an open end. The connection end of the first metal element is coupled to the ground plane, and is adjacent to the first feeding point. The second metal element has a connection end and an open end. The connection end of the second metal element is coupled to the ground plane, and is adjacent to the second feeding point.