An electronic device includes a multi-layer circuit board, a main antenna, and an electronic element. The multi-layer circuit board includes an outer layer, a ground layer, and a plurality of vias defined therein electrically connected the outer layer and the ground layer. The main antenna is mounted on the outer layer and electrically connected to the ground layer by the vias. The electronic element is mounted on the outer layer, soldered on the main antenna, and electrically connected to the ground layer by the main antenna.