Antenna structure

An antenna structure, comprising:

• a first radiation element, coupled to a ground voltage, wherein the first radiation element comprises a variable-width portion;
• a second radiation element, having a feeding point, wherein the second radiation element is adjacent to the first radiation element;
• a third radiation element, coupled to the variable-width portion of the first radiation element;
• a fourth radiation element, coupled to the second radiation element;
• a dielectric substrate, having a first surface and a second surface opposite to each other;
• wherein the second radiation element and the fourth radiation element are disposed on the first surface of the dielectric substrate, and the first radiation element and the third radiation element are disposed on the second surface of the dielectric substrate;
• wherein the antenna structure further comprises:
• a fifth radiation element, coupled to the feeding point, and disposed on the first surface of the dielectric substrate, wherein the fifth radiation element substantially has an L-shape;
• wherein the fifth radiation element has a vertical projection on the second surface of the dielectric substrate, and the vertical projection at least partially overlaps the variable-width portion of the first radiation element.