A wearable electronic device, comprising: a middle frame comprising: a ground device with a system ground contact surface, the system ground contact surface being disposed inside the middle frame; a metallic bottom device with a metallic bottom surface, wherein the ground device is above the metallic bottom device; a plurality of side walls surrounding the metallic bottom device, and a first side wall of the plurality of side walls connected to the metallic bottom device, wherein the first side wall comprises: a first dielectric element connected to the metallic bottom surface of the metallic bottom device; and the first side wall further comprises a first metallic side wall connected to the first dielectric element, wherein the first metallic side wall is isolated from the metallic bottom surface by the first dielectric element, and the first metallic side wall is electrically connected to the system ground contact surface; and a first antenna wiring circuit disposed on the first dielectric element and comprising a first antenna pattern, the first antenna pattern comprising: a first metal portion comprising a first segment, a second segment, and a third segment, the first segment, the second segment, and the third segment being circumferentially connected to form a first slit, the first segment having a first signal feeding terminal, and the third segment having a first ground point; and a second metal portion connected to the third segment and being located in the first slit, the first metallic side wall is arranged to operably perform coupled resonance with the first metal portion and the second metal portion to generate a first resonant frequency band. a ground device with a system ground contact surface, the system ground contact surface being disposed inside the middle frame; a metallic bottom device with a metallic bottom surface, wherein the ground device is above the metallic bottom device; a plurality of side walls surrounding the metallic bottom device, and a first side wall of the plurality of side walls connected to the metallic bottom device, wherein the first side wall comprises: a first dielectric element connected to the metallic bottom surface of the metallic bottom device; and the first side wall further comprises a first metallic side wall connected to the first dielectric element, wherein the first metallic side wall is isolated from the metallic bottom surface by the first dielectric element, and the first metallic side wall is electrically connected to the system ground contact surface; and a first antenna wiring circuit disposed on the first dielectric element and comprising a first antenna pattern, the first antenna pattern comprising: a first metal portion comprising a first segment, a second segment, and a third segment, the first segment, the second segment, and the third segment being circumferentially connected to form a first slit, the first segment having a first signal feeding terminal, and the third segment having a first ground point; and a second metal portion connected to the third segment and being located in the first slit, the first metallic side wall is arranged to operably perform coupled resonance with the first metal portion and the second metal portion to generate a first resonant frequency band. a first dielectric element connected to the metallic bottom surface of the metallic bottom device; and the first side wall further comprises a first metallic side wall connected to the first dielectric element, wherein the first metallic side wall is isolated from the metallic bottom surface by the first dielectric element, and the first metallic side wall is electrically connected to the system ground contact surface; and a first antenna wiring circuit disposed on the first dielectric element and comprising a first antenna pattern, the first antenna pattern comprising: a first metal portion comprising a first segment, a second segment, and a third segment, the first segment, the second segment, and the third segment being circumferentially connected to form a first slit, the first segment having a first signal feeding terminal, and the third segment having a first ground point; and a second metal portion connected to the third segment and being located in the first slit, the first metallic side wall is arranged to operably perform coupled resonance with the first metal portion and the second metal portion to generate a first resonant frequency band. a first metal portion comprising a first segment, a second segment, and a third segment, the first segment, the second segment, and the third segment being circumferentially connected to form a first slit, the first segment having a first signal feeding terminal, and the third segment having a first ground point; and a second metal portion connected to the third segment and being located in the first slit, the first metallic side wall is arranged to operably perform coupled resonance with the first metal portion and the second metal portion to generate a first resonant frequency band.