A coupling antenna has a substrate, an inducting conductor, a ground plane, a first coupling member and a second coupling member. The inducting conductor is mounted on the substrate. The ground plane is formed on and protrudes from the inducting conductor and is mounted on the substrate. The first coupling member is mounted on the substrate and is connected to a feeding cable. The second coupling member is mounted on the substrate and is connected to the first coupling member. The coupling antenna with the first coupling member, the second coupling member and the inducting conductor has a wide bandwidth and a small size.