An electronic device is provided. The electronic device includes a frame structure, and the frame structure includes an outer metallic portion including a first metallic material and forming at least a portion of an outer surface of the electronic device, and an inner metallic portion including a second metallic material different from the first metallic material and laterally surrounded by the outer metallic portion, and a first inner polymeric portion isolated from the inner metallic portion and at least partially laterally surrounded by the outer metallic portion. The electronic device includes a wireless communication circuit electrically connected to a portion of the outer metallic portion.