Antenna structure

An antenna structure, comprising:

• a feeding radiation element, having a feeding point;
• a first radiation element, coupled to the feeding radiation element;
• a second radiation element, coupled to the feeding radiation element, wherein the second radiation element and the first radiation element substantially extend in opposite directions;
• a first coupling branch, comprising a coil portion and a first coupling segment;
• a second coupling branch, wherein the first coupling branch and the second coupling branch are coupled to a common grounding point on a ground element;
• and
• a dielectric substrate, having a first surface and a second surface opposite to each other, wherein the feeding radiation element, the first radiation element, and the second radiation element are distributed over the first surface of the dielectric substrate, and the coil portion of the first coupling branch is distributed over the second surface of the dielectric substrate;
• wherein the feeding radiation element, the first radiation element, and the second radiation element are positioned between the ground element and the first coupling branch or the second coupling branch.