Mobile device with high radiation efficiency

A mobile device with high radiation efficiency, comprising:

• a ground element;
• a first radiation element, having a feeding point;
• a second radiation element, coupled to the first radiation element;
• a third radiation element, wherein the first radiation element is coupled through the third radiation element to the ground element;
• a fourth radiation element, coupled between the first radiation element and the third radiation element;
• and
• a dielectric substrate, wherein the first radiation element, the second radiation element, the third radiation element, and the fourth radiation element are disposed on the dielectric substrate;
• wherein an antenna structure is formed by the first radiation element, the second radiation element, the third radiation element, and the fourth radiation element;
• wherein the fourth radiation element directly touches both of the first radiation element and the third radiation element;
• wherein the mobile device is a convertible notebook computer comprising an upper cover housing, a display frame, a keyboard frame, a base housing, and a support and rotating arm;
• wherein when the convertible notebook computer operates in a tablet mode, the antenna structure is adjacent to a plurality of heat vents of the base housing;
• wherein a distance between the antenna structure and the heat vents of the base housing is longer than or equal to 2 mm.